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 A287069 #10 Oct 08 2017 12:44:38
%S A287069 2,9,13,15,20,22,25,32,34,37,42,49,53,55,58,63,70,72,79,83,85,90,92,
%T A287069 95,100,107,109,116,120,122,125,132,136,138,143,145,148,155,157,160,
%U A287069 165,172,174,181,185,187,190,197,201,203,208,210,213,218,225,229,231
%N A287069 Positions of 2 in A287066.
%H A287069 Clark Kimberling, <a href="/A287069/b287069.txt">Table of n, a(n) for n = 1..10000 </a>
%t A287069 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {1, 2}, 2 -> 0}] &, {1}, 10] (* A287066 *)
%t A287069 Flatten[Position[s, 0]] (* A287067 *)
%t A287069 Flatten[Position[s, 1]] (* A287068 *)
%t A287069 Flatten[Position[s, 2]] (* A287069 *)
%Y A287069 Cf. A287066, A287067, A287068.
%K A287069 nonn,easy
%O A287069 1,1
%A A287069 _Clark Kimberling_, May 21 2017