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 A287453 #4 May 30 2017 12:15:16
%S A287453 2,6,7,10,14,18,21,22,26,30,31,35,38,42,43,46,50,54,55,59,63,66,67,71,
%T A287453 74,78,79,82,86,90,93,94,98,101,105,106,110,114,115,118,122,126,129,
%U A287453 130,134,138,139,143,146,150,151,154,158,162,165,166,170,173,177
%N A287453 Positions of 1 in A287451.
%C A287453 a(n) - a(n-1) is in {1, 3, 4} for n >= 1; also, 3n - a(n) is in {0, 1, 2} for n >= 1. The first 20 numbers 3n - a(n) are 1, 0, 2, 2, 1, 0, 0, 2, 1, 0, 2, 1, 1, 0, 2, 2, 1, 0, 2, 1, with 0 in positions given by A287453, 1 in positions given by A287452, and 2 in positions given by A287454.
%H A287453 Clark Kimberling, <a href="/A287453/b287453.txt">Table of n, a(n) for n = 1..10000</a>
%t A287453 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{2, 0, 1}, 2->{1, 2, 0}}] &, {0}, 9]; (*A287451*)
%t A287453 Flatten[Position[s, 0]]; (*A287452*)
%t A287453 Flatten[Position[s, 1]]; (*A287453*)
%t A287453 Flatten[Position[s, 2]]; (*A287454*)
%Y A287453 Cf. A287451, A287452, A287454.
%K A287453 nonn,easy
%O A287453 1,1
%A A287453 _Clark Kimberling_, May 30 2017