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 A287518 #5 May 30 2017 18:17:14
%S A287518 2,4,9,10,14,18,20,24,25,28,32,36,38,40,45,47,51,52,56,58,63,65,69,70,
%T A287518 73,77,81,82,86,90,92,94,99,101,105,106,110,112,117,118,122,126,128,
%U A287518 132,133,137,139,144,146,150,151,154,158,162,164,166,171,172,176
%N A287518 Positions of 1 in A287516.
%C A287518 a(n) - a(n-1) is in {1, 2, 3, 4, 5} for n >= 1; also, 3n - a(n) is in {0, 1} for n >= 1. The first 20 numbers 3n - a(n) are 1, 2, 0, 2, 1, 0, 1, 0, 2, 2, 1, 0, 1, 2, 0, 1, 0, 2, 1, 2, with 0 in positions given by A287518.
%H A287518 Clark Kimberling, <a href="/A287518/b287518.txt">Table of n, a(n) for n = 1..10000</a>
%t A287518 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 0, 2}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287516*)
%t A287518 Flatten[Position[s, 0]]; (*A287517*)
%t A287518 Flatten[Position[s, 1]]; (*A287518*)
%t A287518 Flatten[Position[s, 2]]; (*A189630*)
%Y A287518 Cf. A287516, A287517, A189630.
%K A287518 nonn,easy
%O A287518 1,1
%A A287518 _Clark Kimberling_, May 30 2017