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 A026513 #22 Nov 29 2020 19:06:35
%S A026513 2,1,2,2,2,1,1,1,2,1,2,2,2,2,2,2,2,1,2,2,2,1,1,1,2,1,1,1,1,1,1,1,2,1,
%T A026513 2,2,2,1,1,1,2,1,2,2,2,2,2,2,2,1,2,2,2,2,2,2,1,2,2,2,2,2,2,2,2,1,2,2,
%U A026513 2,1,1,1,2,1,2,2,2,2,2,2,2,1,2,2,2,1,1,1,2,1
%N A026513 a(n) = t(2+3n), where t = A001285 (Thue-Morse sequence).
%H A026513 Michael De Vlieger, <a href="/A026513/b026513.txt">Table of n, a(n) for n = 0..9999</a>
%t A026513 Array[1 + Mod[DigitCount[3 # + 2, 2, 1], 2] &, 105, 0] (* _Michael De Vlieger_, Oct 06 2019 *)
%t A026513 Table[ThueMorse[2+3n],{n,0,100}]+1 (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Nov 29 2020 *)
%o A026513 (PARI) a(n)=1+hammingweight(3*n+2)%2 \\ _Charles R Greathouse IV_, May 09 2016
%Y A026513 Cf. A001285, A026492, A026498.
%K A026513 nonn
%O A026513 0,1
%A A026513 _Clark Kimberling_
%E A026513 Name and Pari adapted to match offset in A001285 by _Sean A. Irvine_, Oct 05 2019