This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A338502 #9 Nov 03 2020 03:24:50 %S A338502 0,1,5,4,9,8,17,16,25,24,37,21,33,20,13,45,32,29,40,48,65,36,53,72,61, %T A338502 52,80,57,93,64,85,49,81,88,56,96,117,100,68,125,105,116,101,120,112, %U A338502 73,89,137,84,109,141,180,113,133,160,132,161,152,121,144,128 %N A338502 Lexicographically earliest sequence of distinct nonnegative integers such that for any n > 0, a(1) XOR ... XOR a(n) is a square (where XOR denotes the bitwise XOR operator). %C A338502 All terms belong to A042948. %H A338502 Rémy Sigrist, <a href="/A338502/b338502.txt">Table of n, a(n) for n = 1..10000</a> %H A338502 Rémy Sigrist, <a href="/A338502/a338502.gp.txt">PARI program for A338502</a> %e A338502 The first terms, alongside a(1) XOR ... XOR a(n), are: %e A338502 n a(n) a(1) AND ... AND a(n) %e A338502 -- ---- --------------------- %e A338502 1 0 0 = 0^2 %e A338502 2 1 1 = 1^2 %e A338502 3 5 4 = 2^2 %e A338502 4 4 0 = 0^2 %e A338502 5 9 9 = 3^2 %e A338502 6 8 1 = 1^2 %e A338502 7 17 16 = 4^2 %e A338502 8 16 0 = 0^2 %e A338502 9 25 25 = 5^2 %e A338502 10 24 1 = 1^2 %e A338502 11 37 36 = 6^2 %e A338502 12 21 49 = 7^2 %o A338502 (PARI) See Links section. %Y A338502 Cf. A042948, A042964, A292388 (prime variant), A338503. %K A338502 nonn,base %O A338502 1,3 %A A338502 _Rémy Sigrist_, Oct 31 2020