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 A105265 #16 Jul 22 2018 21:58:29
%S A105265 1,1,2,1,2,1,2,3,1,2,1,2,3,1,2,3,1,2,3,4,1,2,1,2,3,1,2,3,1,2,3,4,1,2,
%T A105265 3,1,2,3,4,1,2,3,4,1,2,3,4,1,1,2,1,2,3,1,2,3,1,2,3,4,1,2,3,1,2,3,4,1,
%U A105265 2,3,4,1,2,3,4,1,1,2,3,1,2,3,4,1,2,3,4,1,2,3,4,1,1,2,3,4,1,2,3,4,1,1,2,3,4
%N A105265 Concatenation of letters of words obtained from axiom "1" and the iterates of the substitutions '1' -> "12", '2' -> "3", '3' -> "4", '4' -> "1".
%C A105265 Let W() be the substitution defined above. If we define the sequence S(n) by S(0) = {1}, S(n+1) = S(n) + W(S(n)), then this sequence is the limiting sequence of S(n) as n approaches infinity. - _Charlie Neder_, Jul 11 2018
%H A105265 Charlie Neder, <a href="/A105265/b105265.txt">Table of n, a(n) for n = 0..9999</a>
%t A105265 s[1] = {1, 2}; s[2] = {3}; s[3] = {4}; s[4] = {1};
%t A105265 t[a_] := Join[a, Flatten[s /@ a]];
%t A105265 p[0] = {1}; p[1] = t[{1}]; p[n_] := t[p[n - 1]]
%t A105265 aa = p[6]
%Y A105265 Cf. A073058.
%K A105265 nonn,easy,less
%O A105265 0,3
%A A105265 _Roger L. Bagula_, Apr 15 2005
%E A105265 New name from _Joerg Arndt_, Jul 14 2018