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 A285658 #9 Jun 04 2020 18:20:02
%S A285658 2,8,12,16,20,24,30,34,38,44,48,52,58,62,66,72,76,80,86,90,94,98,102,
%T A285658 108,112,116,122,126,130,136,140,144,148,152,158,162,166,172,176,180,
%U A285658 186,190,194,198,202,208,212,216,222,226,230,236,240,244,248,252
%N A285658 Positions of 0 in A285657; complement of A285659.
%C A285658 Conjecture: a(n)/n -> (5 + sqrt(17))/2.
%H A285658 Clark Kimberling, <a href="/A285658/b285658.txt">Table of n, a(n) for n = 1..10000</a> [term a(8731)=39826 -> 39824 and following corrected by _Georg Fischer_, Jun 04 2020]
%e A285658 As a word, A285657 = 101111101..., in which 0 is in positions 2,8,12,16,...
%t A285658 s = Nest[Flatten[# /. {0 -> {1, 1}, 1 -> {1, 0, 1, 1}}] &, {0}, 10] (* A285657 *)
%t A285658 u = Flatten[Position[s, 0]] (* A285658 *)
%t A285658 Flatten[Position[s, 1]] (* A285659 *)
%t A285658 u/2 (* A286043 *)
%Y A285658 Cf. A285551, A285658, A285659.
%K A285658 nonn,easy
%O A285658 1,1
%A A285658 _Clark Kimberling_, May 01 2017