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 A103682 #7 Sep 11 2023 21:44:43
%S A103682 1,1,2,1,2,1,2,1,2,3,1,2,1,2,1,2,3,1,2,1,2,3,1,2,1,2,3,1,2,1,2,3,1,1,
%T A103682 3,1,2,1,2,1,2,3,1,2,1,2,3,1,2,1,2,3,1,2,1,2,3,1,1,3,1,2,1,2,3,1,2,1,
%U A103682 2,3,1,2,1,2,3,1,1,3,1,2,1,2,3,1,2,1,2,3,1,1,3,1,2,1,2,3,1,2,1,2,3,1,1,3,1
%N A103682 Trajectory of 1 under repeated applications of the morphism 1-> {1,2}, 2->{1,2,3}, 3->{1,1,3}.
%H A103682 <a href="/index/Fi#FIXEDPOINTS">Index entries for sequences that are fixed points of mappings</a>
%t A103682 s[1] = {1, 2}; s[2] = {1, 2, 3}; s[3] = {1, 1, 3}; t[a_] := Join[a, Flatten[s /@ a]]; a = t[t[t[t[t[{1}]]]]]
%Y A103682 Cf. A073058.
%K A103682 nonn
%O A103682 1,3
%A A103682 _Roger L. Bagula_, Mar 26 2005