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 A107297 #15 Jun 30 2023 07:06:12
%S A107297 1,3,1,1,2,1,3,1,1,1,3,1,1,1,1,3,1,1,2,1,3,1,1,1,3,1,1,1,3,1,1,2,1,3,
%T A107297 1,1,1,3,1,1,1,3,1,1,1,3,1,1,2,1,3,1,1,1,3,1,1,1,1,3,1,1,2,1,3,1,1,1,
%U A107297 3,1,1,1,3,1,1,2,1,3,1,1,1,3,1,1,1,3,1,1,2,1,3,1,1,1,3,1,1,1,1,3,1,1,2,1,3
%N A107297 Limit of the string substitution 1->{1, 3, 1, 1}, 2->{1}, 3->{2}.
%t A107297 s[1] = {1, 3, 1, 1}; s[2] = {1}; s[3] = {2};
%t A107297 t[a_] := Flatten[s /@ a];
%t A107297 p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]]
%t A107297 aa = p[5]
%Y A107297 Cf. A106748, A106749.
%K A107297 nonn
%O A107297 1,2
%A A107297 _Roger L. Bagula_, May 20 2005
%E A107297 Edited by and meaningful name from _Joerg Arndt_, Jun 30 2023