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 A287408 #4 May 25 2017 17:54:29
%S A287408 1,6,8,11,15,16,20,22,27,29,31,36,38,42,43,46,51,53,56,58,63,64,69,71,
%T A287408 74,78,79,83,85,90,91,96,98,101,105,106,110,112,117,119,123,124,127,
%U A287408 132,134,136,141,143,146,150,151,155,157,162,164,166,171,172,177
%N A287408 Positions of 0 in A287407.
%C A287408 a(n) - a(n-1) is in {1, 2, 3, 4, 5} for n >= 1; also, 3n - a(n) is in {0, 1, 2} for n >= 1. The first 20 numbers 3n - a(n) are 2, 0, 1, 1, 0, 2, 0, 2, 1, 0, 2, 1, 1, 0, 2, 2, 0, 1, 1, 0, with 0 in positions given by A287403.
%H A287408 Clark Kimberling, <a href="/A287408/b287408.txt">Table of n, a(n) for n = 1..10000</a>
%t A287408 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 1, 0}, 2->{2, 0, 1}}] &, {0}, 9]; (*A287407*)
%t A287408 Flatten[Position[s, 0]]; (*A287408*)
%t A287408 Flatten[Position[s, 1]]; (*A287409*)
%t A287408 Flatten[Position[s, 2]]; (*A287410*)
%Y A287408 Cf. A287407, A287409, A287410.
%K A287408 nonn,easy
%O A287408 1,2
%A A287408 _Clark Kimberling_, May 25 2017