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 A287201 #4 May 23 2017 21:00:07
%S A287201 4,8,10,12,13,14,18,22,26,28,30,31,32,36,38,40,41,42,46,48,50,51,52,
%T A287201 56,57,58,62,63,64,68,72,76,78,80,81,82,86,90,94,96,98,99,100,104,108,
%U A287201 112,114,116,117,118,122,124,126,127,128,132,134,136,137,138
%N A287201 Positions of 0 in A287200.
%H A287201 Clark Kimberling, <a href="/A287201/b287201.txt">Table of n, a(n) for n = 1..10000</a>
%t A287201 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {2, 2}, 2 -> 0}] &, {0}, 11] (* A287200 *)
%t A287201 Flatten[Position[s, 0]] (* A287201 *)
%t A287201 Flatten[Position[s, 1]] (* A287202 *)
%t A287201 Flatten[Position[s, 2]] (* A287203 *)
%Y A287201 Cf. A287200, A287202, A287203.
%K A287201 nonn,easy
%O A287201 1,1
%A A287201 _Clark Kimberling_, May 23 2017