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 A287413 #4 May 26 2017 16:43:11
%S A287413 2,4,9,10,15,17,20,24,25,28,33,35,38,42,43,47,49,54,56,58,63,65,69,70,
%T A287413 73,78,80,82,87,89,92,96,97,101,103,108,110,112,117,119,123,124,127,
%U A287413 132,134,137,139,144,145,150,152,155,159,160,164,166,171,172,177
%N A287413 Positions of 1 in A287411.
%C A287413 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 1, 2, 0, 2, 0, 1, 1, 0, 2, 2, 0, 1, 1, 0, 2, 1, 2, 0, 1, 2, with 0 in positions given by A287414.
%H A287413 Clark Kimberling, <a href="/A287413/b287413.txt">Table of n, a(n) for n = 1..10000</a>
%t A287413 s = Nest[Flatten[# /. {0->{0, 1, 2}, 1->{1, 2, 0}, 2->{0, 2, 1}}] &, {0}, 9]; (*A287411*)
%t A287413 Flatten[Position[s, 0]]; (*A287412*)
%t A287413 Flatten[Position[s, 1]]; (*A287413*)
%t A287413 Flatten[Position[s, 2]]; (*A287414*)
%Y A287413 Cf. A287411, A287412, A287414.
%K A287413 nonn,easy
%O A287413 1,1
%A A287413 _Clark Kimberling_, May 25 2017