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 A287412 #4 May 26 2017 16:43:05
%S A287412 1,6,7,12,13,16,19,22,27,30,31,34,37,40,45,46,51,52,55,60,61,64,67,72,
%T A287412 75,76,79,84,85,88,91,94,99,100,105,106,109,114,115,118,121,126,129,
%U A287412 130,133,136,141,142,147,148,151,154,157,162,163,168,169,174,175
%N A287412 Positions of 0 in A287411.
%C A287412 a(n) - a(n-1) is in {1, 3, 5} for n >= 1; also, 3n - a(n) is in {0, 2} for n >= 1. The first 20 numbers 3n - a(n) are 2, 0, 2, 0, 2, 2, 2, 2, 0, 0, 2, 2, 2, 2, 0, 2, 0, 2, 2, 0, with 0 in positions given by A287413.
%H A287412 Clark Kimberling, <a href="/A287412/b287412.txt">Table of n, a(n) for n = 1..10000</a>
%t A287412 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 2, 0}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287411*)
%t A287412 Flatten[Position[s, 0]]; (*A287412*)
%t A287412 Flatten[Position[s, 1]]; (*A287413*)
%t A287412 Flatten[Position[s, 2]]; (*A287414*)
%Y A287412 Cf. A287411, A287413, A287414.
%K A287412 nonn,easy
%O A287412 1,2
%A A287412 _Clark Kimberling_, May 25 2017