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 A287563 #4 May 31 2017 21:23:58 %S A287563 3,5,10,16,18,24,27,29,33,38,44,47,52,55,57,62,65,70,76,79,84,87,89, %T A287563 94,99,101,106,112,114,120,123,125,130,136,139,141,145,150,156,159, %U A287563 164,167,169,174,179,181,186,192,196,199,201,206,211,213,218,224,226 %N A287563 Positions of 1 in A287561. %C A287563 a(n) - a(n-1) is in {1,2,3,4,5,6} for n >= 1; also, 4n - a(n) is in {0,1,2,3} for n >= 1. The first 20 numbers 4n - a(n) are 1, 3, 2, 0, 2, 0, 1, 3, 3, 2, 0, 1, 0, 1, 3, 2, 3, 2, 0, 1, with %C A287563 0 in positions given by A287565, %C A287563 1 in positions given by A287562, %C A287563 2 in positions given by A287563, %C A287563 3 in positions given by A287564. %H A287563 Clark Kimberling, <a href="/A287563/b287563.txt">Table of n, a(n) for n = 1..10000</a> %t A287563 s = Nest[Flatten[# /. {0 -> {0, 2, 1, 3}, 1 -> {2, 1, 3, 0}, 2 -> {1, 3, 0, 2}, 3 -> {3, 0, 2, 1}}] &, {0}, 9]; (* A287561 *) %t A287563 Flatten[Position[s, 0]]; (* A287562 *) %t A287563 Flatten[Position[s, 1]]; (* A287563 *) %t A287563 Flatten[Position[s, 2]]; (* A287564 *) %t A287563 Flatten[Position[s, 3]]; (* A287565 *) %Y A287563 Cf. A287561, A287562, A287564, A287565. %K A287563 nonn,easy %O A287563 1,1 %A A287563 _Clark Kimberling_, May 31 2017