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 A287075 #4 May 21 2017 14:35:02
%S A287075 3,6,11,15,20,24,27,31,36,40,43,48,52,55,59,64,68,71,76,80,85,89,92,
%T A287075 97,101,104,108,113,117,120,125,129,134,138,141,145,150,154,157,162,
%U A287075 166,171,175,178,183,187,190,194,199,203,206,211,215,220,224,227,231
%N A287075 Positions of 2 in A287072.
%H A287075 Clark Kimberling, <a href="/A287075/b287075.txt">Table of n, a(n) for n = 1..10000</a>
%t A287075 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {2, 1}, 2 -> 0}] &, {0}, 10] (* A287072 *)
%t A287075 Flatten[Position[s, 0]] (* A287073 *)
%t A287075 Flatten[Position[s, 1]] (* A287074 *)
%t A287075 Flatten[Position[s, 2]] (* A287075 *)
%Y A287075 Cf. A287072, A287073, A287074.
%K A287075 nonn,easy
%O A287075 1,1
%A A287075 _Clark Kimberling_, May 21 2017