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 A277745 #8 Jan 21 2018 09:35:47
%S A277745 1,2,3,2,1,2,3,2,2,3,2,1,2,3,2,3,2,1,2,3,2,2,3,2,1,2,3,2,1,2,3,2,2,3,
%T A277745 2,1,2,3,2,3,2,1,2,3,2,2,3,2,1,2,3,2,2,3,2,1,2,3,2,3,2,1,2,3,2,2,3,2,
%U A277745 1,2,3,2,1,2,3,2,2,3,2,1,2,3,2,3,2,1,2,3,2,2,3,2,1,2,3,2,3,2,1,2,3
%N A277745 Trajectory of 1 under repeated application of the morphism 1 -> 1232, 2 -> 1232232, 3 -> 123232.
%C A277745 This is A275925 put into Dekking's standard form.
%H A277745 F. Michel Dekking, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL19/Dekking/dekk4.html">Morphisms, Symbolic Sequences, and Their Standard Forms</a>, Journal of Integer Sequences, Vol. 19 (2016), Article 16.1.1.
%p A277745 with(ListTools);
%p A277745 psi:=proc(S)
%p A277745 Flatten(subs( {1=[1,2,3,2], 2=[1,2,3,2,2,3,2], 3=[1,2,3,2,3,2]}, S));
%p A277745 end;
%p A277745 S:=[1];
%p A277745 for n from 1 to 4 do S:=psi(S): od:
%p A277745 S;
%t A277745 SubstitutionSystem[{1 -> {1, 2, 3, 2}, 2 -> {1, 2, 3, 2, 2, 3, 2}, 3 -> {1, 2, 3, 2, 3, 2}}, {1}, 3] // Last (* _Jean-François Alcover_, Jan 21 2018 *)
%Y A277745 Cf. A275925, A276790.
%K A277745 nonn
%O A277745 1,2
%A A277745 _N. J. A. Sloane_, Nov 08 2016