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 A026492 #21 Oct 07 2019 14:45:31 %S A026492 1,1,1,1,1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,2,1,1,1,2,2,2,1,2,1,1, %T A026492 1,1,1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,1,2,1,2,2,2,1,1,1,2,1,1,1,1,1, %U A026492 1,1,1,2,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,2,1,1 %N A026492 a(n) = t(3n), where t = A001285 (Thue-Morse sequence). %H A026492 Michael De Vlieger, <a href="/A026492/b026492.txt">Table of n, a(n) for n = 0..10000</a> %H A026492 Michael Gilleland, <a href="/selfsimilar.html">Some Self-Similar Integer Sequences</a> %t A026492 Array[1 + Mod[DigitCount[3 #, 2, 1], 2] &, 105, 0] (* _Michael De Vlieger_, Oct 03 2019 *) %o A026492 (PARI) a(n)=1+hammingweight(3*n)%2 \\ _Charles R Greathouse IV_, May 09 2016 %Y A026492 Cf. A001285, A026498, A026513. %K A026492 nonn %O A026492 0,8 %A A026492 _Clark Kimberling_ %E A026492 Name and Pari adapted to match offset in A001285 by _Sean A. Irvine_, Oct 02 2019