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 A287444 #4 May 29 2017 23:58:35
%S A287444 1,5,7,10,13,17,19,22,26,28,31,35,37,41,43,46,49,53,55,59,61,64,67,71,
%T A287444 73,76,80,82,86,88,91,94,98,100,103,107,109,113,115,118,121,125,127,
%U A287444 130,134,136,139,143,145,149,151,154,157,161,163,167,169,172,175
%N A287444 Positions of 0 in A287443.
%C A287444 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, 2, 2, 1, 2, 2, 1, 2, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, with 1 in positions given by A287443.
%H A287444 Clark Kimberling, <a href="/A287444/b287444.txt">Table of n, a(n) for n = 1..10000</a>
%t A287444 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 0, 1}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287443*)
%t A287444 Flatten[Position[s, 0]]; (*A287444*)
%t A287444 Flatten[Position[s, 1]]; (*A287445*)
%t A287444 Flatten[Position[s, 2]]; (*A287446*)
%Y A287444 Cf. A287443, A287445, A287446.
%K A287444 nonn,easy
%O A287444 1,2
%A A287444 _Clark Kimberling_, May 26 2017