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 A286999 #4 May 22 2017 20:02:42
%S A286999 1,3,5,7,9,11,13,14,16,18,20,22,24,25,27,29,31,33,35,37,38,40,42,44,
%T A286999 46,48,50,51,53,55,57,59,61,62,64,66,68,70,72,74,75,77,79,81,82,84,86,
%U A286999 88,90,92,94,95,97,99,101,103,105,106,108,110,112,114,116
%N A286999 Positions of 0 in A286998.
%H A286999 Clark Kimberling, <a href="/A286999/b286999.txt">Table of n, a(n) for n = 1..10000</a>
%t A286999 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {2, 0}, 2 -> 0}] &, {0}, 9] (* A286998 *)
%t A286999 Flatten[Position[s, 0]] (* A286999 *)
%t A286999 Flatten[Position[s, 1]] (* A287000 *)
%t A286999 Flatten[Position[s, 2]] (* A287001 *)
%Y A286999 Cf. A286998, A287000, A287001.
%K A286999 nonn,easy
%O A286999 1,2
%A A286999 _Clark Kimberling_, May 22 2017