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 A287517 #8 May 31 2017 03:10:06
%S A287517 1,5,7,11,13,16,19,22,26,29,31,34,37,41,43,46,49,53,55,59,61,64,67,71,
%T A287517 74,76,79,83,85,88,91,95,97,100,103,107,109,113,115,119,121,124,127,
%U A287517 130,134,136,140,142,145,148,152,155,157,160,163,167,169,173,175
%N A287517 Positions of 0 in A287516.
%C A287517 a(n) - a(n-1) is in {2, 3, 4} for n >= 1; also, 3n - a(n) is in {1, 2} for n >= 1. The first 20 numbers 3n - a(n) are 2, 1, 2, 1, 2, 2, 2, 2, 1, 1, 2, 2, 2, 1, 2, 2, 2, 1, 2, 1, with 1 in positions given by A287518.
%H A287517 Clark Kimberling, <a href="/A287517/b287517.txt">Table of n, a(n) for n = 1..10000</a>
%t A287517 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 0, 2}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287516*)
%t A287517 Flatten[Position[s, 0]]; (*A287517*)
%t A287517 Flatten[Position[s, 1]]; (*A287518*)
%t A287517 Flatten[Position[s, 2]]; (*A189630*)
%Y A287517 Cf. A287516, A287518, A189630.
%K A287517 nonn,easy
%O A287517 1,2
%A A287517 _Clark Kimberling_, May 30 2017