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 A285680 #8 Jul 27 2024 04:51:16
%S A285680 0,1,0,0,2,0,1,0,0,2,0,2,0,1,0,0,2,0,1,0,0,2,0,2,0,1,0,0,2,0,2,0,1,0,
%T A285680 0,2,0,1,0,0,2,0,2,0,1,0,0,2,0,1,0,0,2,0,2,0,1,0,0,2,0,2,0,1,0,0,2,0,
%U A285680 1,0,0,2,0,2,0,1,0,0,2,0,2,0,1,0,0,2
%N A285680 {1010->2}-transform of the infinite Fibonacci word A003849.
%H A285680 Clark Kimberling, <a href="/A285680/b285680.txt">Table of n, a(n) for n = 1..10000</a>
%e A285680 As a word, A003849 = 01001010010010100..., and replacing each 1010 by 2 gives 01002010020201002010020201002020100201...
%t A285680 s = Nest[Flatten[# /. {0 -> {0, 1}, 1 -> {0}}] &, {0}, 13] ; (* A003849 *)
%t A285680 w = StringJoin[Map[ToString, s]]
%t A285680 w1 = StringReplace[w, {"1010" -> "2"}]
%t A285680 st = ToCharacterCode[w1] - 48; (* A285680 *)
%t A285680 Flatten[Position[st, 0]]; (* A285681 *)
%t A285680 Flatten[Position[st, 1]]; (* A285682 *)
%t A285680 Flatten[Position[st, 2]]; (* A285683 *)
%Y A285680 Cf. A003849, A285677, A285681, A285682, A285683.
%K A285680 nonn,easy
%O A285680 1,5
%A A285680 _Clark Kimberling_, May 11 2017