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 A287115 #4 May 22 2017 20:03:15
%S A287115 3,10,14,21,27,34,41,47,54,58,65,71,78,82,89,95,102,109,115,122,126,
%T A287115 133,139,146,152,159,163,170,176,183,190,196,203,207,214,220,227,234,
%U A287115 240,247,251,258,264,271,277,284,288,295,301,308,315,321,328,332,339
%N A287115 Positions of 2 in A287112.
%H A287115 Clark Kimberling, <a href="/A287115/b287115.txt">Table of n, a(n) for n = 1..10000</a>
%t A287115 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {2, 0}, 2 -> 0}] &, {0}, 10] (* A287112 *)
%t A287115 Flatten[Position[s, 0]] (* A287113 *)
%t A287115 Flatten[Position[s, 1]] (* A287114 *)
%t A287115 Flatten[Position[s, 2]] (* A287115 *)
%Y A287115 Cf. A287112, A287113, A287114.
%K A287115 nonn,easy
%O A287115 1,1
%A A287115 _Clark Kimberling_, May 22 2017