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 A285342 #8 Apr 25 2017 17:19:58
%S A285342 2,6,8,12,16,20,22,26,28,32,36,40,42,46,50,54,56,60,64,68,70,74,76,80,
%T A285342 84,88,90,94,96,100,104,108,110,114,118,122,124,128,132,136,138,142,
%U A285342 144,148,152,156,158,162,166,170,172,176,180,184,186,190,192,196
%N A285342 Positions of 0 in A285341; complement of A285343.
%C A285342 Conjecture: 0 < n*r - a(n) < 4 for n>=1, where r = 2 + sqrt(2).
%H A285342 Clark Kimberling, <a href="/A285342/b285342.txt">Table of n, a(n) for n = 1..10000</a>
%e A285342 As a word, A285341 = 1011101..., in which 0 is in positions 2,6,8,12,16,...
%t A285342 s = Nest[Flatten[# /. {0 -> {1, 0}, 1 -> {1, 0, 1, 1}}] &, {0}, 10]; (* A285341 *)
%t A285342 u = Flatten[Position[s, 0]]; (* A285342 *)
%t A285342 Flatten[Position[s, 1]]; (* A285343 *)
%t A285342 u/2 (* A285344)
%Y A285342 Cf. A285341, A285343, A285344.
%K A285342 nonn,easy
%O A285342 1,1
%A A285342 _Clark Kimberling_, Apr 25 2017