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 A287414 #4 May 26 2017 16:43:16
%S A287414 3,5,8,11,14,18,21,23,26,29,32,36,39,41,44,48,50,53,57,59,62,66,68,71,
%T A287414 74,77,81,83,86,90,93,95,98,102,104,107,111,113,116,120,122,125,128,
%U A287414 131,135,138,140,143,146,149,153,156,158,161,165,167,170,173,176
%N A287414 Positions of 2 in A287411.
%C A287414 a(n) - a(n-1) is in {2,3,4} for n >= 1; also, 3n - a(n) is in {0, 1} for n >= 1. The first 20 numbers 3n - a(n) are 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 1, with 0 in positions given by A287412.
%H A287414 Clark Kimberling, <a href="/A287414/b287414.txt">Table of n, a(n) for n = 1..10000</a>
%t A287414 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 2, 0}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287411*)
%t A287414 Flatten[Position[s, 0]]; (*A287412*)
%t A287414 Flatten[Position[s, 1]]; (*A287413*)
%t A287414 Flatten[Position[s, 2]]; (*A287414*)
%Y A287414 Cf. A287411, A287412, A287413.
%K A287414 nonn,easy
%O A287414 1,1
%A A287414 _Clark Kimberling_, May 25 2017