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 A287176 #4 May 22 2017 20:03:48
%S A287176 3,6,10,12,16,19,23,26,30,32,36,39,43,47,50,54,56,60,63,67,69,73,76,
%T A287176 80,84,87,91,93,97,100,104,107,111,113,117,120,124,128,131,135,137,
%U A287176 141,144,148,151,155,157,161,164,168,172,175,179,181,185,188,192,194
%N A287176 Positions of 1 in A287174.
%t A287176 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {2, 0}, 2 -> 0}] &, {0}, 11] (* A287174 *)
%t A287176 Flatten[Position[s, 0]] (* A287175 *)
%t A287176 Flatten[Position[s, 1]] (* A287176 *)
%t A287176 Flatten[Position[s, 2]] (* A287177 *)
%Y A287176 Cf. A287174, A287175, A287177.
%K A287176 nonn,easy
%O A287176 1,1
%A A287176 _Clark Kimberling_, May 22 2017