New Order #2: Turn My Way












15












$begingroup$


Introduction (may be ignored)



Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. This is the second challenge in this series. The first challenge can be found here.



In this challenge, we use Gray codes to rearrage the natural numbers. A Gray code, or "reflected binary code" is a binary encoding in such a way that two successive values differ in only one bit. A practical application of this encoding is to use it in rotary encoders, hence my reference to "Turn My Way".



Rotary encoder for angle-measuring devices marked in 3-bit binary.



Note that this encoding leaves some degree of freedom. For example, following binary 1100, there are four possible following codes: 1101, 1110, 1000 and 0100. This is why I will define $a(n)$ as the smallest, not previously used value that differs only one character in binary encoding. This sequence corresponds with A163252.



Since this is a "pure sequence" challenge, the task is to output $a(n)$ for a given $n$ as input, where $a(n)$ is A163252.



Task



Given an integer input $n$, output $a(n)$ in integer format (not in binary format).



$a(n)$ is defined as the least positive integer not occurring earlier in the sequence such that $a(n-1)$ and $a(n)$ differ in only one bit when written in binary.



Note: 1-based indexing is assumed here; you may use 0-based indexing, so $a(0) = 1; a(1) = 3$, etc. Please mention this in your answer if you choose to use this.



Test cases



Input | Output
--------------
1 | 1
5 | 4
20 | 18
50 | 48
123 | 121
1234 | 1333
3000 | 3030
9999 | 9997


Rules




  • Input and output are integers (your program should at least support input and output in the range of 1 up to 32767)

  • Invalid input (0, floats, strings, negative values, etc.) may lead to unpredicted output, errors or (un)defined behaviour. In A163252, $a(0)$ is defined as 0. For this challenge, we will ignore this.

  • Default I/O rules apply.


  • Default loopholes are forbidden.

  • This is code-golf, so the shortest answers in bytes wins


Final note



See the following related (but not equal) PP&CG questions:




  • Finding the next Gray code (input and output in binary)

  • Generate the all Gray codes of length n










share|improve this question









$endgroup$

















    15












    $begingroup$


    Introduction (may be ignored)



    Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. This is the second challenge in this series. The first challenge can be found here.



    In this challenge, we use Gray codes to rearrage the natural numbers. A Gray code, or "reflected binary code" is a binary encoding in such a way that two successive values differ in only one bit. A practical application of this encoding is to use it in rotary encoders, hence my reference to "Turn My Way".



    Rotary encoder for angle-measuring devices marked in 3-bit binary.



    Note that this encoding leaves some degree of freedom. For example, following binary 1100, there are four possible following codes: 1101, 1110, 1000 and 0100. This is why I will define $a(n)$ as the smallest, not previously used value that differs only one character in binary encoding. This sequence corresponds with A163252.



    Since this is a "pure sequence" challenge, the task is to output $a(n)$ for a given $n$ as input, where $a(n)$ is A163252.



    Task



    Given an integer input $n$, output $a(n)$ in integer format (not in binary format).



    $a(n)$ is defined as the least positive integer not occurring earlier in the sequence such that $a(n-1)$ and $a(n)$ differ in only one bit when written in binary.



    Note: 1-based indexing is assumed here; you may use 0-based indexing, so $a(0) = 1; a(1) = 3$, etc. Please mention this in your answer if you choose to use this.



    Test cases



    Input | Output
    --------------
    1 | 1
    5 | 4
    20 | 18
    50 | 48
    123 | 121
    1234 | 1333
    3000 | 3030
    9999 | 9997


    Rules




    • Input and output are integers (your program should at least support input and output in the range of 1 up to 32767)

    • Invalid input (0, floats, strings, negative values, etc.) may lead to unpredicted output, errors or (un)defined behaviour. In A163252, $a(0)$ is defined as 0. For this challenge, we will ignore this.

    • Default I/O rules apply.


    • Default loopholes are forbidden.

    • This is code-golf, so the shortest answers in bytes wins


    Final note



    See the following related (but not equal) PP&CG questions:




    • Finding the next Gray code (input and output in binary)

    • Generate the all Gray codes of length n










    share|improve this question









    $endgroup$















      15












      15








      15





      $begingroup$


      Introduction (may be ignored)



      Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. This is the second challenge in this series. The first challenge can be found here.



      In this challenge, we use Gray codes to rearrage the natural numbers. A Gray code, or "reflected binary code" is a binary encoding in such a way that two successive values differ in only one bit. A practical application of this encoding is to use it in rotary encoders, hence my reference to "Turn My Way".



      Rotary encoder for angle-measuring devices marked in 3-bit binary.



      Note that this encoding leaves some degree of freedom. For example, following binary 1100, there are four possible following codes: 1101, 1110, 1000 and 0100. This is why I will define $a(n)$ as the smallest, not previously used value that differs only one character in binary encoding. This sequence corresponds with A163252.



      Since this is a "pure sequence" challenge, the task is to output $a(n)$ for a given $n$ as input, where $a(n)$ is A163252.



      Task



      Given an integer input $n$, output $a(n)$ in integer format (not in binary format).



      $a(n)$ is defined as the least positive integer not occurring earlier in the sequence such that $a(n-1)$ and $a(n)$ differ in only one bit when written in binary.



      Note: 1-based indexing is assumed here; you may use 0-based indexing, so $a(0) = 1; a(1) = 3$, etc. Please mention this in your answer if you choose to use this.



      Test cases



      Input | Output
      --------------
      1 | 1
      5 | 4
      20 | 18
      50 | 48
      123 | 121
      1234 | 1333
      3000 | 3030
      9999 | 9997


      Rules




      • Input and output are integers (your program should at least support input and output in the range of 1 up to 32767)

      • Invalid input (0, floats, strings, negative values, etc.) may lead to unpredicted output, errors or (un)defined behaviour. In A163252, $a(0)$ is defined as 0. For this challenge, we will ignore this.

      • Default I/O rules apply.


      • Default loopholes are forbidden.

      • This is code-golf, so the shortest answers in bytes wins


      Final note



      See the following related (but not equal) PP&CG questions:




      • Finding the next Gray code (input and output in binary)

      • Generate the all Gray codes of length n










      share|improve this question









      $endgroup$




      Introduction (may be ignored)



      Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. This is the second challenge in this series. The first challenge can be found here.



      In this challenge, we use Gray codes to rearrage the natural numbers. A Gray code, or "reflected binary code" is a binary encoding in such a way that two successive values differ in only one bit. A practical application of this encoding is to use it in rotary encoders, hence my reference to "Turn My Way".



      Rotary encoder for angle-measuring devices marked in 3-bit binary.



      Note that this encoding leaves some degree of freedom. For example, following binary 1100, there are four possible following codes: 1101, 1110, 1000 and 0100. This is why I will define $a(n)$ as the smallest, not previously used value that differs only one character in binary encoding. This sequence corresponds with A163252.



      Since this is a "pure sequence" challenge, the task is to output $a(n)$ for a given $n$ as input, where $a(n)$ is A163252.



      Task



      Given an integer input $n$, output $a(n)$ in integer format (not in binary format).



      $a(n)$ is defined as the least positive integer not occurring earlier in the sequence such that $a(n-1)$ and $a(n)$ differ in only one bit when written in binary.



      Note: 1-based indexing is assumed here; you may use 0-based indexing, so $a(0) = 1; a(1) = 3$, etc. Please mention this in your answer if you choose to use this.



      Test cases



      Input | Output
      --------------
      1 | 1
      5 | 4
      20 | 18
      50 | 48
      123 | 121
      1234 | 1333
      3000 | 3030
      9999 | 9997


      Rules




      • Input and output are integers (your program should at least support input and output in the range of 1 up to 32767)

      • Invalid input (0, floats, strings, negative values, etc.) may lead to unpredicted output, errors or (un)defined behaviour. In A163252, $a(0)$ is defined as 0. For this challenge, we will ignore this.

      • Default I/O rules apply.


      • Default loopholes are forbidden.

      • This is code-golf, so the shortest answers in bytes wins


      Final note



      See the following related (but not equal) PP&CG questions:




      • Finding the next Gray code (input and output in binary)

      • Generate the all Gray codes of length n







      code-golf sequence






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked yesterday









      agtoeveragtoever

      1,158421




      1,158421






















          10 Answers
          10






          active

          oldest

          votes


















          4












          $begingroup$

          JavaScript (ES6), 65 bytes



          1-indexed.





          n=>{for(o=p=[k=1];o[k]|~-(i=p^k)&i?k++:k=o[p=k]=!!n--;);return p}


          Try it online!



          Commented



          n => {                  // n = index of requested term
          for( // for loop:
          o = // o = storage object for the terms of the sequence
          p = // p = last term found in the sequence
          [k = 1]; // k = current term
          o[k] | // if k was already encountered
          ~-(i = p ^ k) & i ? // or (p XOR k) has more than 1 bit set:
          k++ // increment k
          : // else:
          k = o[p = k] // set o[k], set p to k
          = !!n--; // stop if n is equal to 0 or set k to 1; decrement n
          ); // end of for()
          return p // return p
          } // end





          share|improve this answer











          $endgroup$













          • $begingroup$
            On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
            $endgroup$
            – agtoever
            yesterday






          • 1




            $begingroup$
            @agtoever I've updated it to a non-recursive version.
            $endgroup$
            – Arnauld
            yesterday



















          4












          $begingroup$


          Jelly, 26 20 bytes



          ṀBLŻ2*^1ị$ḟ⁸Ṃ;
          0Ç⁸¡Ḣ


          Try it online!



          A full program that takes n as the single argument. Works for all test cases. Also note that, although not required, it handles n=0.



          Explanation



          Helper link: find next term and prepend



          Ṁ              | maximum of list so far
          B | convert to binary
          L | number of binary digits
          Ż | 0..above number
          2* | 2 to the power of each of the above
          ^ | exclusive or with...
          1ị$ | ... the most recent term in the list so far
          ḟ⁸ | filter out anything used already
          Ṃ | find the minimum
          ; | prepend to existing list


          Main link



          0              | start with zero
          Ç | call the above link
          ⁸¡ | and repeat n times
          Ḣ | take the last term added





          share|improve this answer











          $endgroup$





















            3












            $begingroup$


            Java (JDK), 142 138 124 123 132 130 98 bytes




            • increased to account for import, saved a byte thanks to @kevin-cruijssen

            • switched collection to int array thanks to @olivier-grégoire


            n->{int s=new int[9*n],j,k=0;for(;n-->0;s[k=j]++)for(j=0;s[++j]>0|n.bitCount(j^k)>1;);return k;}


            Try it online!






            share|improve this answer











            $endgroup$









            • 1




              $begingroup$
              I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
              $endgroup$
              – Kevin Cruijssen
              21 hours ago






            • 1




              $begingroup$
              Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
              $endgroup$
              – Daniel Widdis
              20 hours ago






            • 1




              $begingroup$
              Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
              $endgroup$
              – Kevin Cruijssen
              20 hours ago






            • 2




              $begingroup$
              You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
              $endgroup$
              – Kevin Cruijssen
              19 hours ago








            • 2




              $begingroup$
              98 bytes.
              $endgroup$
              – Olivier Grégoire
              19 hours ago



















            1












            $begingroup$


            Wolfram Language (Mathematica), 74 bytes



            Last@Nest[#~Join~{Min[BitXor[Last@#,2^Range[0,20]]~Complement~#]}&,{0},#]&


            Try it online!






            share|improve this answer









            $endgroup$





















              1












              $begingroup$


              APL (Dyalog Extended), 46 bytes





              {⍵⌷2∘{(~⍺∊⍵)∧1=≢⍸≠⌿↑⌽∘⊤¨⍺,⊃⌽⍵:⍵,⍺⋄⍵∇⍨⍺+1}⍣⍵⊢1}


              Try it online!






              share|improve this answer









              $endgroup$





















                1












                $begingroup$


                Stax, 19 bytes



                ±↔Φd┌û╓°╡ñ|Q5┌¿Éúb≈


                Run and debug it



                It's very slow, but not nearly as slow as the 17 byte solution I was working on. I think there's still some golfing potential. I will add an explanation after I get rid of the bloat.






                share|improve this answer











                $endgroup$





















                  1












                  $begingroup$


                  Charcoal, 65 bytes



                  ≔⁰θFN«⊞υθ≔¹ηW¬‹θ⊗η≦⊗ηW∧›η¹∨¬&θη№υ⁻θη≧÷²ηW№υ⁻|θη&θη≦⊗η≔⁻|θη&θηθ»Iθ


                  Try it online! Link is to verbose version of code. Explanation:



                  ≔⁰θ


                  Initialise the result to 0.



                  FN«


                  Loop n times.



                  ⊞υθ


                  Save the previous result so that we don't use it again.



                  ≔¹ηW¬‹θ⊗η≦⊗η


                  Find the highest bit in the previous result.



                  W∧›η¹∨¬&θη№υ⁻θη≧÷²η


                  While that bit is greater than 1, if the bit is set in the previous result, try subtracting that bit to see if the result is an unseen result. This ensures that the potential results are tried in ascending order of value.



                  W№υ⁻|θη&θη≦⊗η


                  Now try XORing that bit with the previous result, doubling the bit until an unseen result is found. This handles the cases when a bit needs to be set, again in ascending order of value, but also the case when the least significant bit needs to be toggled, which the previous loop doesn't bother to test (because it's golfier to test for that here). If the previous loop found an unseen result then this loop never runs; if it didn't then this loop will uselessly retest those results.



                  ≔⁻|θη&θηθ


                  Update the result by actually XORing the bit with it.



                  »Iθ


                  Output the final result at the end of the loop.






                  share|improve this answer









                  $endgroup$





















                    1












                    $begingroup$


                    05AB1E, 21 20 18 bytes



                    ÎFˆ∞.Δ¯θy^bSO¯yå_*


                    Pretty inefficient, so the larger the input, the longer it takes to get the result. Does work for input 0 as well, though.



                    Try it online or verify the first $n$ terms.



                    Explanation:





                    Î                # Push 0 and the input
                    F # Loop the input amount of times:
                    ˆ # Pop the current number and add it to the global_array
                    ∞.Δ # Inner loop starting at 1 to find the first number which is truthy for:
                    ¯θy^ # XOR the last number of the global_array with the loop-number `y`
                    b # Convert it to binary
                    SO # Sum it's binary digits
                    ¯yå_ # Check if the loop-number `y` is NOT in the global_array yet
                    * # Multiply both (only if this is 1 (truthy), the inner loop will stop)
                    # (after the loops, output the top of the stack implicitly)





                    share|improve this answer











                    $endgroup$





















                      1












                      $begingroup$


                      Python 2, 81 bytes



                      1-based indexing





                      l=[0];p=0
                      exec"n=0nwhile(p^n)&(p^n)-1or n in l:n+=1np=n;l+=p,;"*input()
                      print p


                      Try it online!






                      Python 2, 79 bytes



                      This takes a lot of time (9999 wasn't finished after running locally for 7 minutes)





                      l={0};p=0;n=input()
                      exec'p=min({p^2**k for k in range(n)}-l);l|={p};'*n
                      print p


                      Try it online!






                      share|improve this answer











                      $endgroup$









                      • 1




                        $begingroup$
                        Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                        $endgroup$
                        – Erik the Outgolfer
                        yesterday










                      • $begingroup$
                        Even the given test case 9999 isn't supported. :)
                        $endgroup$
                        – Daniel Widdis
                        21 hours ago










                      • $begingroup$
                        @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                        $endgroup$
                        – ovs
                        19 hours ago










                      • $begingroup$
                        @ovs Oh, timeouts alone don't matter.
                        $endgroup$
                        – Erik the Outgolfer
                        17 hours ago



















                      0












                      $begingroup$


                      Haskell, 101 bytes





                      import Data.Bits
                      (u!n)0=n
                      (u!n)m|q<-minimum[x|r<-[0..62],x<-[xor(2^r)n],notElem x u]=(n:u)!q$m-1
                      !0


                      Try it online!



                      It seems a shame to incur an import just for xor, but I haven't found a good work-around yet. I also wonder if there's a better way to express the loop.






                      share|improve this answer











                      $endgroup$













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                        10 Answers
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                        4












                        $begingroup$

                        JavaScript (ES6), 65 bytes



                        1-indexed.





                        n=>{for(o=p=[k=1];o[k]|~-(i=p^k)&i?k++:k=o[p=k]=!!n--;);return p}


                        Try it online!



                        Commented



                        n => {                  // n = index of requested term
                        for( // for loop:
                        o = // o = storage object for the terms of the sequence
                        p = // p = last term found in the sequence
                        [k = 1]; // k = current term
                        o[k] | // if k was already encountered
                        ~-(i = p ^ k) & i ? // or (p XOR k) has more than 1 bit set:
                        k++ // increment k
                        : // else:
                        k = o[p = k] // set o[k], set p to k
                        = !!n--; // stop if n is equal to 0 or set k to 1; decrement n
                        ); // end of for()
                        return p // return p
                        } // end





                        share|improve this answer











                        $endgroup$













                        • $begingroup$
                          On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                          $endgroup$
                          – agtoever
                          yesterday






                        • 1




                          $begingroup$
                          @agtoever I've updated it to a non-recursive version.
                          $endgroup$
                          – Arnauld
                          yesterday
















                        4












                        $begingroup$

                        JavaScript (ES6), 65 bytes



                        1-indexed.





                        n=>{for(o=p=[k=1];o[k]|~-(i=p^k)&i?k++:k=o[p=k]=!!n--;);return p}


                        Try it online!



                        Commented



                        n => {                  // n = index of requested term
                        for( // for loop:
                        o = // o = storage object for the terms of the sequence
                        p = // p = last term found in the sequence
                        [k = 1]; // k = current term
                        o[k] | // if k was already encountered
                        ~-(i = p ^ k) & i ? // or (p XOR k) has more than 1 bit set:
                        k++ // increment k
                        : // else:
                        k = o[p = k] // set o[k], set p to k
                        = !!n--; // stop if n is equal to 0 or set k to 1; decrement n
                        ); // end of for()
                        return p // return p
                        } // end





                        share|improve this answer











                        $endgroup$













                        • $begingroup$
                          On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                          $endgroup$
                          – agtoever
                          yesterday






                        • 1




                          $begingroup$
                          @agtoever I've updated it to a non-recursive version.
                          $endgroup$
                          – Arnauld
                          yesterday














                        4












                        4








                        4





                        $begingroup$

                        JavaScript (ES6), 65 bytes



                        1-indexed.





                        n=>{for(o=p=[k=1];o[k]|~-(i=p^k)&i?k++:k=o[p=k]=!!n--;);return p}


                        Try it online!



                        Commented



                        n => {                  // n = index of requested term
                        for( // for loop:
                        o = // o = storage object for the terms of the sequence
                        p = // p = last term found in the sequence
                        [k = 1]; // k = current term
                        o[k] | // if k was already encountered
                        ~-(i = p ^ k) & i ? // or (p XOR k) has more than 1 bit set:
                        k++ // increment k
                        : // else:
                        k = o[p = k] // set o[k], set p to k
                        = !!n--; // stop if n is equal to 0 or set k to 1; decrement n
                        ); // end of for()
                        return p // return p
                        } // end





                        share|improve this answer











                        $endgroup$



                        JavaScript (ES6), 65 bytes



                        1-indexed.





                        n=>{for(o=p=[k=1];o[k]|~-(i=p^k)&i?k++:k=o[p=k]=!!n--;);return p}


                        Try it online!



                        Commented



                        n => {                  // n = index of requested term
                        for( // for loop:
                        o = // o = storage object for the terms of the sequence
                        p = // p = last term found in the sequence
                        [k = 1]; // k = current term
                        o[k] | // if k was already encountered
                        ~-(i = p ^ k) & i ? // or (p XOR k) has more than 1 bit set:
                        k++ // increment k
                        : // else:
                        k = o[p = k] // set o[k], set p to k
                        = !!n--; // stop if n is equal to 0 or set k to 1; decrement n
                        ); // end of for()
                        return p // return p
                        } // end






                        share|improve this answer














                        share|improve this answer



                        share|improve this answer








                        edited yesterday

























                        answered yesterday









                        ArnauldArnauld

                        79.4k796330




                        79.4k796330












                        • $begingroup$
                          On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                          $endgroup$
                          – agtoever
                          yesterday






                        • 1




                          $begingroup$
                          @agtoever I've updated it to a non-recursive version.
                          $endgroup$
                          – Arnauld
                          yesterday


















                        • $begingroup$
                          On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                          $endgroup$
                          – agtoever
                          yesterday






                        • 1




                          $begingroup$
                          @agtoever I've updated it to a non-recursive version.
                          $endgroup$
                          – Arnauld
                          yesterday
















                        $begingroup$
                        On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                        $endgroup$
                        – agtoever
                        yesterday




                        $begingroup$
                        On TIO, I get a stack overflow for n > ~1024. Any suggestions on how tot deal with that in Abu other environment? Rule: "your program should at least support input and output in theorie range of 1 up tot 32767"
                        $endgroup$
                        – agtoever
                        yesterday




                        1




                        1




                        $begingroup$
                        @agtoever I've updated it to a non-recursive version.
                        $endgroup$
                        – Arnauld
                        yesterday




                        $begingroup$
                        @agtoever I've updated it to a non-recursive version.
                        $endgroup$
                        – Arnauld
                        yesterday











                        4












                        $begingroup$


                        Jelly, 26 20 bytes



                        ṀBLŻ2*^1ị$ḟ⁸Ṃ;
                        0Ç⁸¡Ḣ


                        Try it online!



                        A full program that takes n as the single argument. Works for all test cases. Also note that, although not required, it handles n=0.



                        Explanation



                        Helper link: find next term and prepend



                        Ṁ              | maximum of list so far
                        B | convert to binary
                        L | number of binary digits
                        Ż | 0..above number
                        2* | 2 to the power of each of the above
                        ^ | exclusive or with...
                        1ị$ | ... the most recent term in the list so far
                        ḟ⁸ | filter out anything used already
                        Ṃ | find the minimum
                        ; | prepend to existing list


                        Main link



                        0              | start with zero
                        Ç | call the above link
                        ⁸¡ | and repeat n times
                        Ḣ | take the last term added





                        share|improve this answer











                        $endgroup$


















                          4












                          $begingroup$


                          Jelly, 26 20 bytes



                          ṀBLŻ2*^1ị$ḟ⁸Ṃ;
                          0Ç⁸¡Ḣ


                          Try it online!



                          A full program that takes n as the single argument. Works for all test cases. Also note that, although not required, it handles n=0.



                          Explanation



                          Helper link: find next term and prepend



                          Ṁ              | maximum of list so far
                          B | convert to binary
                          L | number of binary digits
                          Ż | 0..above number
                          2* | 2 to the power of each of the above
                          ^ | exclusive or with...
                          1ị$ | ... the most recent term in the list so far
                          ḟ⁸ | filter out anything used already
                          Ṃ | find the minimum
                          ; | prepend to existing list


                          Main link



                          0              | start with zero
                          Ç | call the above link
                          ⁸¡ | and repeat n times
                          Ḣ | take the last term added





                          share|improve this answer











                          $endgroup$
















                            4












                            4








                            4





                            $begingroup$


                            Jelly, 26 20 bytes



                            ṀBLŻ2*^1ị$ḟ⁸Ṃ;
                            0Ç⁸¡Ḣ


                            Try it online!



                            A full program that takes n as the single argument. Works for all test cases. Also note that, although not required, it handles n=0.



                            Explanation



                            Helper link: find next term and prepend



                            Ṁ              | maximum of list so far
                            B | convert to binary
                            L | number of binary digits
                            Ż | 0..above number
                            2* | 2 to the power of each of the above
                            ^ | exclusive or with...
                            1ị$ | ... the most recent term in the list so far
                            ḟ⁸ | filter out anything used already
                            Ṃ | find the minimum
                            ; | prepend to existing list


                            Main link



                            0              | start with zero
                            Ç | call the above link
                            ⁸¡ | and repeat n times
                            Ḣ | take the last term added





                            share|improve this answer











                            $endgroup$




                            Jelly, 26 20 bytes



                            ṀBLŻ2*^1ị$ḟ⁸Ṃ;
                            0Ç⁸¡Ḣ


                            Try it online!



                            A full program that takes n as the single argument. Works for all test cases. Also note that, although not required, it handles n=0.



                            Explanation



                            Helper link: find next term and prepend



                            Ṁ              | maximum of list so far
                            B | convert to binary
                            L | number of binary digits
                            Ż | 0..above number
                            2* | 2 to the power of each of the above
                            ^ | exclusive or with...
                            1ị$ | ... the most recent term in the list so far
                            ḟ⁸ | filter out anything used already
                            Ṃ | find the minimum
                            ; | prepend to existing list


                            Main link



                            0              | start with zero
                            Ç | call the above link
                            ⁸¡ | and repeat n times
                            Ḣ | take the last term added






                            share|improve this answer














                            share|improve this answer



                            share|improve this answer








                            edited yesterday

























                            answered yesterday









                            Nick KennedyNick Kennedy

                            82137




                            82137























                                3












                                $begingroup$


                                Java (JDK), 142 138 124 123 132 130 98 bytes




                                • increased to account for import, saved a byte thanks to @kevin-cruijssen

                                • switched collection to int array thanks to @olivier-grégoire


                                n->{int s=new int[9*n],j,k=0;for(;n-->0;s[k=j]++)for(j=0;s[++j]>0|n.bitCount(j^k)>1;);return k;}


                                Try it online!






                                share|improve this answer











                                $endgroup$









                                • 1




                                  $begingroup$
                                  I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  21 hours ago






                                • 1




                                  $begingroup$
                                  Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                  $endgroup$
                                  – Daniel Widdis
                                  20 hours ago






                                • 1




                                  $begingroup$
                                  Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                  $endgroup$
                                  – Kevin Cruijssen
                                  20 hours ago






                                • 2




                                  $begingroup$
                                  You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  19 hours ago








                                • 2




                                  $begingroup$
                                  98 bytes.
                                  $endgroup$
                                  – Olivier Grégoire
                                  19 hours ago
















                                3












                                $begingroup$


                                Java (JDK), 142 138 124 123 132 130 98 bytes




                                • increased to account for import, saved a byte thanks to @kevin-cruijssen

                                • switched collection to int array thanks to @olivier-grégoire


                                n->{int s=new int[9*n],j,k=0;for(;n-->0;s[k=j]++)for(j=0;s[++j]>0|n.bitCount(j^k)>1;);return k;}


                                Try it online!






                                share|improve this answer











                                $endgroup$









                                • 1




                                  $begingroup$
                                  I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  21 hours ago






                                • 1




                                  $begingroup$
                                  Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                  $endgroup$
                                  – Daniel Widdis
                                  20 hours ago






                                • 1




                                  $begingroup$
                                  Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                  $endgroup$
                                  – Kevin Cruijssen
                                  20 hours ago






                                • 2




                                  $begingroup$
                                  You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  19 hours ago








                                • 2




                                  $begingroup$
                                  98 bytes.
                                  $endgroup$
                                  – Olivier Grégoire
                                  19 hours ago














                                3












                                3








                                3





                                $begingroup$


                                Java (JDK), 142 138 124 123 132 130 98 bytes




                                • increased to account for import, saved a byte thanks to @kevin-cruijssen

                                • switched collection to int array thanks to @olivier-grégoire


                                n->{int s=new int[9*n],j,k=0;for(;n-->0;s[k=j]++)for(j=0;s[++j]>0|n.bitCount(j^k)>1;);return k;}


                                Try it online!






                                share|improve this answer











                                $endgroup$




                                Java (JDK), 142 138 124 123 132 130 98 bytes




                                • increased to account for import, saved a byte thanks to @kevin-cruijssen

                                • switched collection to int array thanks to @olivier-grégoire


                                n->{int s=new int[9*n],j,k=0;for(;n-->0;s[k=j]++)for(j=0;s[++j]>0|n.bitCount(j^k)>1;);return k;}


                                Try it online!







                                share|improve this answer














                                share|improve this answer



                                share|improve this answer








                                edited 10 hours ago

























                                answered 23 hours ago









                                Daniel WiddisDaniel Widdis

                                1495




                                1495








                                • 1




                                  $begingroup$
                                  I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  21 hours ago






                                • 1




                                  $begingroup$
                                  Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                  $endgroup$
                                  – Daniel Widdis
                                  20 hours ago






                                • 1




                                  $begingroup$
                                  Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                  $endgroup$
                                  – Kevin Cruijssen
                                  20 hours ago






                                • 2




                                  $begingroup$
                                  You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  19 hours ago








                                • 2




                                  $begingroup$
                                  98 bytes.
                                  $endgroup$
                                  – Olivier Grégoire
                                  19 hours ago














                                • 1




                                  $begingroup$
                                  I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  21 hours ago






                                • 1




                                  $begingroup$
                                  Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                  $endgroup$
                                  – Daniel Widdis
                                  20 hours ago






                                • 1




                                  $begingroup$
                                  Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                  $endgroup$
                                  – Kevin Cruijssen
                                  20 hours ago






                                • 2




                                  $begingroup$
                                  You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                  $endgroup$
                                  – Kevin Cruijssen
                                  19 hours ago








                                • 2




                                  $begingroup$
                                  98 bytes.
                                  $endgroup$
                                  – Olivier Grégoire
                                  19 hours ago








                                1




                                1




                                $begingroup$
                                I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                $endgroup$
                                – Kevin Cruijssen
                                21 hours ago




                                $begingroup$
                                I'm afraid imports has to be included in the byte-count. You can however golf the import java.util.*;+Set s=new HashSet(); to var s=new java.util.HashSet();. In addition, the rest can be golfed to: Integer i=0,j,k=0;for(;i++<n;s.add(k=j))for(j=0;s.contains(++j)|i.bitCount(j^k)>1;);return k;. Nice answer nonetheless, so +1 from me. :)
                                $endgroup$
                                – Kevin Cruijssen
                                21 hours ago




                                1




                                1




                                $begingroup$
                                Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                $endgroup$
                                – Daniel Widdis
                                20 hours ago




                                $begingroup$
                                Saved 2 more bytes using Stack rather than HashSet. A lot slower but works!
                                $endgroup$
                                – Daniel Widdis
                                20 hours ago




                                1




                                1




                                $begingroup$
                                Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                $endgroup$
                                – Kevin Cruijssen
                                20 hours ago




                                $begingroup$
                                Ah, of course, smart. And no matter how slow, if we can save a byte it's worth it for code-golf challenges. ;p I once had an answer that went from complexity $O(n)$ to $O(n^n)$ by saving a byte, haha xD
                                $endgroup$
                                – Kevin Cruijssen
                                20 hours ago




                                2




                                2




                                $begingroup$
                                You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                $endgroup$
                                – Kevin Cruijssen
                                19 hours ago






                                $begingroup$
                                You can still golf it to 126 bytes with the second golf I suggested in my first comment. :)
                                $endgroup$
                                – Kevin Cruijssen
                                19 hours ago






                                2




                                2




                                $begingroup$
                                98 bytes.
                                $endgroup$
                                – Olivier Grégoire
                                19 hours ago




                                $begingroup$
                                98 bytes.
                                $endgroup$
                                – Olivier Grégoire
                                19 hours ago











                                1












                                $begingroup$


                                Wolfram Language (Mathematica), 74 bytes



                                Last@Nest[#~Join~{Min[BitXor[Last@#,2^Range[0,20]]~Complement~#]}&,{0},#]&


                                Try it online!






                                share|improve this answer









                                $endgroup$


















                                  1












                                  $begingroup$


                                  Wolfram Language (Mathematica), 74 bytes



                                  Last@Nest[#~Join~{Min[BitXor[Last@#,2^Range[0,20]]~Complement~#]}&,{0},#]&


                                  Try it online!






                                  share|improve this answer









                                  $endgroup$
















                                    1












                                    1








                                    1





                                    $begingroup$


                                    Wolfram Language (Mathematica), 74 bytes



                                    Last@Nest[#~Join~{Min[BitXor[Last@#,2^Range[0,20]]~Complement~#]}&,{0},#]&


                                    Try it online!






                                    share|improve this answer









                                    $endgroup$




                                    Wolfram Language (Mathematica), 74 bytes



                                    Last@Nest[#~Join~{Min[BitXor[Last@#,2^Range[0,20]]~Complement~#]}&,{0},#]&


                                    Try it online!







                                    share|improve this answer












                                    share|improve this answer



                                    share|improve this answer










                                    answered yesterday









                                    J42161217J42161217

                                    13.3k21251




                                    13.3k21251























                                        1












                                        $begingroup$


                                        APL (Dyalog Extended), 46 bytes





                                        {⍵⌷2∘{(~⍺∊⍵)∧1=≢⍸≠⌿↑⌽∘⊤¨⍺,⊃⌽⍵:⍵,⍺⋄⍵∇⍨⍺+1}⍣⍵⊢1}


                                        Try it online!






                                        share|improve this answer









                                        $endgroup$


















                                          1












                                          $begingroup$


                                          APL (Dyalog Extended), 46 bytes





                                          {⍵⌷2∘{(~⍺∊⍵)∧1=≢⍸≠⌿↑⌽∘⊤¨⍺,⊃⌽⍵:⍵,⍺⋄⍵∇⍨⍺+1}⍣⍵⊢1}


                                          Try it online!






                                          share|improve this answer









                                          $endgroup$
















                                            1












                                            1








                                            1





                                            $begingroup$


                                            APL (Dyalog Extended), 46 bytes





                                            {⍵⌷2∘{(~⍺∊⍵)∧1=≢⍸≠⌿↑⌽∘⊤¨⍺,⊃⌽⍵:⍵,⍺⋄⍵∇⍨⍺+1}⍣⍵⊢1}


                                            Try it online!






                                            share|improve this answer









                                            $endgroup$




                                            APL (Dyalog Extended), 46 bytes





                                            {⍵⌷2∘{(~⍺∊⍵)∧1=≢⍸≠⌿↑⌽∘⊤¨⍺,⊃⌽⍵:⍵,⍺⋄⍵∇⍨⍺+1}⍣⍵⊢1}


                                            Try it online!







                                            share|improve this answer












                                            share|improve this answer



                                            share|improve this answer










                                            answered yesterday









                                            voidhawkvoidhawk

                                            1,34125




                                            1,34125























                                                1












                                                $begingroup$


                                                Stax, 19 bytes



                                                ±↔Φd┌û╓°╡ñ|Q5┌¿Éúb≈


                                                Run and debug it



                                                It's very slow, but not nearly as slow as the 17 byte solution I was working on. I think there's still some golfing potential. I will add an explanation after I get rid of the bloat.






                                                share|improve this answer











                                                $endgroup$


















                                                  1












                                                  $begingroup$


                                                  Stax, 19 bytes



                                                  ±↔Φd┌û╓°╡ñ|Q5┌¿Éúb≈


                                                  Run and debug it



                                                  It's very slow, but not nearly as slow as the 17 byte solution I was working on. I think there's still some golfing potential. I will add an explanation after I get rid of the bloat.






                                                  share|improve this answer











                                                  $endgroup$
















                                                    1












                                                    1








                                                    1





                                                    $begingroup$


                                                    Stax, 19 bytes



                                                    ±↔Φd┌û╓°╡ñ|Q5┌¿Éúb≈


                                                    Run and debug it



                                                    It's very slow, but not nearly as slow as the 17 byte solution I was working on. I think there's still some golfing potential. I will add an explanation after I get rid of the bloat.






                                                    share|improve this answer











                                                    $endgroup$




                                                    Stax, 19 bytes



                                                    ±↔Φd┌û╓°╡ñ|Q5┌¿Éúb≈


                                                    Run and debug it



                                                    It's very slow, but not nearly as slow as the 17 byte solution I was working on. I think there's still some golfing potential. I will add an explanation after I get rid of the bloat.







                                                    share|improve this answer














                                                    share|improve this answer



                                                    share|improve this answer








                                                    edited yesterday

























                                                    answered yesterday









                                                    recursiverecursive

                                                    5,5891322




                                                    5,5891322























                                                        1












                                                        $begingroup$


                                                        Charcoal, 65 bytes



                                                        ≔⁰θFN«⊞υθ≔¹ηW¬‹θ⊗η≦⊗ηW∧›η¹∨¬&θη№υ⁻θη≧÷²ηW№υ⁻|θη&θη≦⊗η≔⁻|θη&θηθ»Iθ


                                                        Try it online! Link is to verbose version of code. Explanation:



                                                        ≔⁰θ


                                                        Initialise the result to 0.



                                                        FN«


                                                        Loop n times.



                                                        ⊞υθ


                                                        Save the previous result so that we don't use it again.



                                                        ≔¹ηW¬‹θ⊗η≦⊗η


                                                        Find the highest bit in the previous result.



                                                        W∧›η¹∨¬&θη№υ⁻θη≧÷²η


                                                        While that bit is greater than 1, if the bit is set in the previous result, try subtracting that bit to see if the result is an unseen result. This ensures that the potential results are tried in ascending order of value.



                                                        W№υ⁻|θη&θη≦⊗η


                                                        Now try XORing that bit with the previous result, doubling the bit until an unseen result is found. This handles the cases when a bit needs to be set, again in ascending order of value, but also the case when the least significant bit needs to be toggled, which the previous loop doesn't bother to test (because it's golfier to test for that here). If the previous loop found an unseen result then this loop never runs; if it didn't then this loop will uselessly retest those results.



                                                        ≔⁻|θη&θηθ


                                                        Update the result by actually XORing the bit with it.



                                                        »Iθ


                                                        Output the final result at the end of the loop.






                                                        share|improve this answer









                                                        $endgroup$


















                                                          1












                                                          $begingroup$


                                                          Charcoal, 65 bytes



                                                          ≔⁰θFN«⊞υθ≔¹ηW¬‹θ⊗η≦⊗ηW∧›η¹∨¬&θη№υ⁻θη≧÷²ηW№υ⁻|θη&θη≦⊗η≔⁻|θη&θηθ»Iθ


                                                          Try it online! Link is to verbose version of code. Explanation:



                                                          ≔⁰θ


                                                          Initialise the result to 0.



                                                          FN«


                                                          Loop n times.



                                                          ⊞υθ


                                                          Save the previous result so that we don't use it again.



                                                          ≔¹ηW¬‹θ⊗η≦⊗η


                                                          Find the highest bit in the previous result.



                                                          W∧›η¹∨¬&θη№υ⁻θη≧÷²η


                                                          While that bit is greater than 1, if the bit is set in the previous result, try subtracting that bit to see if the result is an unseen result. This ensures that the potential results are tried in ascending order of value.



                                                          W№υ⁻|θη&θη≦⊗η


                                                          Now try XORing that bit with the previous result, doubling the bit until an unseen result is found. This handles the cases when a bit needs to be set, again in ascending order of value, but also the case when the least significant bit needs to be toggled, which the previous loop doesn't bother to test (because it's golfier to test for that here). If the previous loop found an unseen result then this loop never runs; if it didn't then this loop will uselessly retest those results.



                                                          ≔⁻|θη&θηθ


                                                          Update the result by actually XORing the bit with it.



                                                          »Iθ


                                                          Output the final result at the end of the loop.






                                                          share|improve this answer









                                                          $endgroup$
















                                                            1












                                                            1








                                                            1





                                                            $begingroup$


                                                            Charcoal, 65 bytes



                                                            ≔⁰θFN«⊞υθ≔¹ηW¬‹θ⊗η≦⊗ηW∧›η¹∨¬&θη№υ⁻θη≧÷²ηW№υ⁻|θη&θη≦⊗η≔⁻|θη&θηθ»Iθ


                                                            Try it online! Link is to verbose version of code. Explanation:



                                                            ≔⁰θ


                                                            Initialise the result to 0.



                                                            FN«


                                                            Loop n times.



                                                            ⊞υθ


                                                            Save the previous result so that we don't use it again.



                                                            ≔¹ηW¬‹θ⊗η≦⊗η


                                                            Find the highest bit in the previous result.



                                                            W∧›η¹∨¬&θη№υ⁻θη≧÷²η


                                                            While that bit is greater than 1, if the bit is set in the previous result, try subtracting that bit to see if the result is an unseen result. This ensures that the potential results are tried in ascending order of value.



                                                            W№υ⁻|θη&θη≦⊗η


                                                            Now try XORing that bit with the previous result, doubling the bit until an unseen result is found. This handles the cases when a bit needs to be set, again in ascending order of value, but also the case when the least significant bit needs to be toggled, which the previous loop doesn't bother to test (because it's golfier to test for that here). If the previous loop found an unseen result then this loop never runs; if it didn't then this loop will uselessly retest those results.



                                                            ≔⁻|θη&θηθ


                                                            Update the result by actually XORing the bit with it.



                                                            »Iθ


                                                            Output the final result at the end of the loop.






                                                            share|improve this answer









                                                            $endgroup$




                                                            Charcoal, 65 bytes



                                                            ≔⁰θFN«⊞υθ≔¹ηW¬‹θ⊗η≦⊗ηW∧›η¹∨¬&θη№υ⁻θη≧÷²ηW№υ⁻|θη&θη≦⊗η≔⁻|θη&θηθ»Iθ


                                                            Try it online! Link is to verbose version of code. Explanation:



                                                            ≔⁰θ


                                                            Initialise the result to 0.



                                                            FN«


                                                            Loop n times.



                                                            ⊞υθ


                                                            Save the previous result so that we don't use it again.



                                                            ≔¹ηW¬‹θ⊗η≦⊗η


                                                            Find the highest bit in the previous result.



                                                            W∧›η¹∨¬&θη№υ⁻θη≧÷²η


                                                            While that bit is greater than 1, if the bit is set in the previous result, try subtracting that bit to see if the result is an unseen result. This ensures that the potential results are tried in ascending order of value.



                                                            W№υ⁻|θη&θη≦⊗η


                                                            Now try XORing that bit with the previous result, doubling the bit until an unseen result is found. This handles the cases when a bit needs to be set, again in ascending order of value, but also the case when the least significant bit needs to be toggled, which the previous loop doesn't bother to test (because it's golfier to test for that here). If the previous loop found an unseen result then this loop never runs; if it didn't then this loop will uselessly retest those results.



                                                            ≔⁻|θη&θηθ


                                                            Update the result by actually XORing the bit with it.



                                                            »Iθ


                                                            Output the final result at the end of the loop.







                                                            share|improve this answer












                                                            share|improve this answer



                                                            share|improve this answer










                                                            answered yesterday









                                                            NeilNeil

                                                            81.9k745178




                                                            81.9k745178























                                                                1












                                                                $begingroup$


                                                                05AB1E, 21 20 18 bytes



                                                                ÎFˆ∞.Δ¯θy^bSO¯yå_*


                                                                Pretty inefficient, so the larger the input, the longer it takes to get the result. Does work for input 0 as well, though.



                                                                Try it online or verify the first $n$ terms.



                                                                Explanation:





                                                                Î                # Push 0 and the input
                                                                F # Loop the input amount of times:
                                                                ˆ # Pop the current number and add it to the global_array
                                                                ∞.Δ # Inner loop starting at 1 to find the first number which is truthy for:
                                                                ¯θy^ # XOR the last number of the global_array with the loop-number `y`
                                                                b # Convert it to binary
                                                                SO # Sum it's binary digits
                                                                ¯yå_ # Check if the loop-number `y` is NOT in the global_array yet
                                                                * # Multiply both (only if this is 1 (truthy), the inner loop will stop)
                                                                # (after the loops, output the top of the stack implicitly)





                                                                share|improve this answer











                                                                $endgroup$


















                                                                  1












                                                                  $begingroup$


                                                                  05AB1E, 21 20 18 bytes



                                                                  ÎFˆ∞.Δ¯θy^bSO¯yå_*


                                                                  Pretty inefficient, so the larger the input, the longer it takes to get the result. Does work for input 0 as well, though.



                                                                  Try it online or verify the first $n$ terms.



                                                                  Explanation:





                                                                  Î                # Push 0 and the input
                                                                  F # Loop the input amount of times:
                                                                  ˆ # Pop the current number and add it to the global_array
                                                                  ∞.Δ # Inner loop starting at 1 to find the first number which is truthy for:
                                                                  ¯θy^ # XOR the last number of the global_array with the loop-number `y`
                                                                  b # Convert it to binary
                                                                  SO # Sum it's binary digits
                                                                  ¯yå_ # Check if the loop-number `y` is NOT in the global_array yet
                                                                  * # Multiply both (only if this is 1 (truthy), the inner loop will stop)
                                                                  # (after the loops, output the top of the stack implicitly)





                                                                  share|improve this answer











                                                                  $endgroup$
















                                                                    1












                                                                    1








                                                                    1





                                                                    $begingroup$


                                                                    05AB1E, 21 20 18 bytes



                                                                    ÎFˆ∞.Δ¯θy^bSO¯yå_*


                                                                    Pretty inefficient, so the larger the input, the longer it takes to get the result. Does work for input 0 as well, though.



                                                                    Try it online or verify the first $n$ terms.



                                                                    Explanation:





                                                                    Î                # Push 0 and the input
                                                                    F # Loop the input amount of times:
                                                                    ˆ # Pop the current number and add it to the global_array
                                                                    ∞.Δ # Inner loop starting at 1 to find the first number which is truthy for:
                                                                    ¯θy^ # XOR the last number of the global_array with the loop-number `y`
                                                                    b # Convert it to binary
                                                                    SO # Sum it's binary digits
                                                                    ¯yå_ # Check if the loop-number `y` is NOT in the global_array yet
                                                                    * # Multiply both (only if this is 1 (truthy), the inner loop will stop)
                                                                    # (after the loops, output the top of the stack implicitly)





                                                                    share|improve this answer











                                                                    $endgroup$




                                                                    05AB1E, 21 20 18 bytes



                                                                    ÎFˆ∞.Δ¯θy^bSO¯yå_*


                                                                    Pretty inefficient, so the larger the input, the longer it takes to get the result. Does work for input 0 as well, though.



                                                                    Try it online or verify the first $n$ terms.



                                                                    Explanation:





                                                                    Î                # Push 0 and the input
                                                                    F # Loop the input amount of times:
                                                                    ˆ # Pop the current number and add it to the global_array
                                                                    ∞.Δ # Inner loop starting at 1 to find the first number which is truthy for:
                                                                    ¯θy^ # XOR the last number of the global_array with the loop-number `y`
                                                                    b # Convert it to binary
                                                                    SO # Sum it's binary digits
                                                                    ¯yå_ # Check if the loop-number `y` is NOT in the global_array yet
                                                                    * # Multiply both (only if this is 1 (truthy), the inner loop will stop)
                                                                    # (after the loops, output the top of the stack implicitly)






                                                                    share|improve this answer














                                                                    share|improve this answer



                                                                    share|improve this answer








                                                                    edited 19 hours ago

























                                                                    answered 20 hours ago









                                                                    Kevin CruijssenKevin Cruijssen

                                                                    41k566211




                                                                    41k566211























                                                                        1












                                                                        $begingroup$


                                                                        Python 2, 81 bytes



                                                                        1-based indexing





                                                                        l=[0];p=0
                                                                        exec"n=0nwhile(p^n)&(p^n)-1or n in l:n+=1np=n;l+=p,;"*input()
                                                                        print p


                                                                        Try it online!






                                                                        Python 2, 79 bytes



                                                                        This takes a lot of time (9999 wasn't finished after running locally for 7 minutes)





                                                                        l={0};p=0;n=input()
                                                                        exec'p=min({p^2**k for k in range(n)}-l);l|={p};'*n
                                                                        print p


                                                                        Try it online!






                                                                        share|improve this answer











                                                                        $endgroup$









                                                                        • 1




                                                                          $begingroup$
                                                                          Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          yesterday










                                                                        • $begingroup$
                                                                          Even the given test case 9999 isn't supported. :)
                                                                          $endgroup$
                                                                          – Daniel Widdis
                                                                          21 hours ago










                                                                        • $begingroup$
                                                                          @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                          $endgroup$
                                                                          – ovs
                                                                          19 hours ago










                                                                        • $begingroup$
                                                                          @ovs Oh, timeouts alone don't matter.
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          17 hours ago
















                                                                        1












                                                                        $begingroup$


                                                                        Python 2, 81 bytes



                                                                        1-based indexing





                                                                        l=[0];p=0
                                                                        exec"n=0nwhile(p^n)&(p^n)-1or n in l:n+=1np=n;l+=p,;"*input()
                                                                        print p


                                                                        Try it online!






                                                                        Python 2, 79 bytes



                                                                        This takes a lot of time (9999 wasn't finished after running locally for 7 minutes)





                                                                        l={0};p=0;n=input()
                                                                        exec'p=min({p^2**k for k in range(n)}-l);l|={p};'*n
                                                                        print p


                                                                        Try it online!






                                                                        share|improve this answer











                                                                        $endgroup$









                                                                        • 1




                                                                          $begingroup$
                                                                          Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          yesterday










                                                                        • $begingroup$
                                                                          Even the given test case 9999 isn't supported. :)
                                                                          $endgroup$
                                                                          – Daniel Widdis
                                                                          21 hours ago










                                                                        • $begingroup$
                                                                          @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                          $endgroup$
                                                                          – ovs
                                                                          19 hours ago










                                                                        • $begingroup$
                                                                          @ovs Oh, timeouts alone don't matter.
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          17 hours ago














                                                                        1












                                                                        1








                                                                        1





                                                                        $begingroup$


                                                                        Python 2, 81 bytes



                                                                        1-based indexing





                                                                        l=[0];p=0
                                                                        exec"n=0nwhile(p^n)&(p^n)-1or n in l:n+=1np=n;l+=p,;"*input()
                                                                        print p


                                                                        Try it online!






                                                                        Python 2, 79 bytes



                                                                        This takes a lot of time (9999 wasn't finished after running locally for 7 minutes)





                                                                        l={0};p=0;n=input()
                                                                        exec'p=min({p^2**k for k in range(n)}-l);l|={p};'*n
                                                                        print p


                                                                        Try it online!






                                                                        share|improve this answer











                                                                        $endgroup$




                                                                        Python 2, 81 bytes



                                                                        1-based indexing





                                                                        l=[0];p=0
                                                                        exec"n=0nwhile(p^n)&(p^n)-1or n in l:n+=1np=n;l+=p,;"*input()
                                                                        print p


                                                                        Try it online!






                                                                        Python 2, 79 bytes



                                                                        This takes a lot of time (9999 wasn't finished after running locally for 7 minutes)





                                                                        l={0};p=0;n=input()
                                                                        exec'p=min({p^2**k for k in range(n)}-l);l|={p};'*n
                                                                        print p


                                                                        Try it online!







                                                                        share|improve this answer














                                                                        share|improve this answer



                                                                        share|improve this answer








                                                                        edited 19 hours ago

























                                                                        answered yesterday









                                                                        ovsovs

                                                                        19.3k21160




                                                                        19.3k21160








                                                                        • 1




                                                                          $begingroup$
                                                                          Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          yesterday










                                                                        • $begingroup$
                                                                          Even the given test case 9999 isn't supported. :)
                                                                          $endgroup$
                                                                          – Daniel Widdis
                                                                          21 hours ago










                                                                        • $begingroup$
                                                                          @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                          $endgroup$
                                                                          – ovs
                                                                          19 hours ago










                                                                        • $begingroup$
                                                                          @ovs Oh, timeouts alone don't matter.
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          17 hours ago














                                                                        • 1




                                                                          $begingroup$
                                                                          Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          yesterday










                                                                        • $begingroup$
                                                                          Even the given test case 9999 isn't supported. :)
                                                                          $endgroup$
                                                                          – Daniel Widdis
                                                                          21 hours ago










                                                                        • $begingroup$
                                                                          @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                          $endgroup$
                                                                          – ovs
                                                                          19 hours ago










                                                                        • $begingroup$
                                                                          @ovs Oh, timeouts alone don't matter.
                                                                          $endgroup$
                                                                          – Erik the Outgolfer
                                                                          17 hours ago








                                                                        1




                                                                        1




                                                                        $begingroup$
                                                                        Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                        $endgroup$
                                                                        – Erik the Outgolfer
                                                                        yesterday




                                                                        $begingroup$
                                                                        Maximum input 32767 isn't supported (the default recursion depth isn't system-dependent).
                                                                        $endgroup$
                                                                        – Erik the Outgolfer
                                                                        yesterday












                                                                        $begingroup$
                                                                        Even the given test case 9999 isn't supported. :)
                                                                        $endgroup$
                                                                        – Daniel Widdis
                                                                        21 hours ago




                                                                        $begingroup$
                                                                        Even the given test case 9999 isn't supported. :)
                                                                        $endgroup$
                                                                        – Daniel Widdis
                                                                        21 hours ago












                                                                        $begingroup$
                                                                        @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                        $endgroup$
                                                                        – ovs
                                                                        19 hours ago




                                                                        $begingroup$
                                                                        @EriktheOutgolfer Changed it to an iterative approach, probably still doesn't finish in time on TIO, but runs locally just fine.
                                                                        $endgroup$
                                                                        – ovs
                                                                        19 hours ago












                                                                        $begingroup$
                                                                        @ovs Oh, timeouts alone don't matter.
                                                                        $endgroup$
                                                                        – Erik the Outgolfer
                                                                        17 hours ago




                                                                        $begingroup$
                                                                        @ovs Oh, timeouts alone don't matter.
                                                                        $endgroup$
                                                                        – Erik the Outgolfer
                                                                        17 hours ago











                                                                        0












                                                                        $begingroup$


                                                                        Haskell, 101 bytes





                                                                        import Data.Bits
                                                                        (u!n)0=n
                                                                        (u!n)m|q<-minimum[x|r<-[0..62],x<-[xor(2^r)n],notElem x u]=(n:u)!q$m-1
                                                                        !0


                                                                        Try it online!



                                                                        It seems a shame to incur an import just for xor, but I haven't found a good work-around yet. I also wonder if there's a better way to express the loop.






                                                                        share|improve this answer











                                                                        $endgroup$


















                                                                          0












                                                                          $begingroup$


                                                                          Haskell, 101 bytes





                                                                          import Data.Bits
                                                                          (u!n)0=n
                                                                          (u!n)m|q<-minimum[x|r<-[0..62],x<-[xor(2^r)n],notElem x u]=(n:u)!q$m-1
                                                                          !0


                                                                          Try it online!



                                                                          It seems a shame to incur an import just for xor, but I haven't found a good work-around yet. I also wonder if there's a better way to express the loop.






                                                                          share|improve this answer











                                                                          $endgroup$
















                                                                            0












                                                                            0








                                                                            0





                                                                            $begingroup$


                                                                            Haskell, 101 bytes





                                                                            import Data.Bits
                                                                            (u!n)0=n
                                                                            (u!n)m|q<-minimum[x|r<-[0..62],x<-[xor(2^r)n],notElem x u]=(n:u)!q$m-1
                                                                            !0


                                                                            Try it online!



                                                                            It seems a shame to incur an import just for xor, but I haven't found a good work-around yet. I also wonder if there's a better way to express the loop.






                                                                            share|improve this answer











                                                                            $endgroup$




                                                                            Haskell, 101 bytes





                                                                            import Data.Bits
                                                                            (u!n)0=n
                                                                            (u!n)m|q<-minimum[x|r<-[0..62],x<-[xor(2^r)n],notElem x u]=(n:u)!q$m-1
                                                                            !0


                                                                            Try it online!



                                                                            It seems a shame to incur an import just for xor, but I haven't found a good work-around yet. I also wonder if there's a better way to express the loop.







                                                                            share|improve this answer














                                                                            share|improve this answer



                                                                            share|improve this answer








                                                                            edited 8 hours ago

























                                                                            answered 8 hours ago









                                                                            dfeuerdfeuer

                                                                            895910




                                                                            895910






























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                                                                                If this is an answer to a challenge…




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                                                                                • …Try to optimize your score. For instance, answers to code-golf challenges should attempt to be as short as possible. You can always include a readable version of the code in addition to the competitive one.
                                                                                  Explanations of your answer make it more interesting to read and are very much encouraged.


                                                                                • …Include a short header which indicates the language(s) of your code and its score, as defined by the challenge.



                                                                                More generally…




                                                                                • …Please make sure to answer the question and provide sufficient detail.


                                                                                • …Avoid asking for help, clarification or responding to other answers (use comments instead).





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