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 A245555 #24 Oct 04 2020 23:39:35
%S A245555 1,2,2,3,2,3,3,1,2,3,3,1,3,1,1,2,2,3,3,1,3,1,1,2,3,1,1,2,1,2,2,3,2,3,
%T A245555 3,1,3,1,1,2,3,1,1,2,1,2,2,3,3,1,1,2,1,2,2,3,1,2,2,3,2,3,3,1,2,3,3,1,
%U A245555 3,1,1,2,3,1,1,2,1,2,2,3,3,1,1,2,1,2,2,3,1,2,2,3
%N A245555 Trajectory of 1 under the morphism 1 -> 12, 2 -> 23, 3 -> 31.
%C A245555 The morphism 1->12, 2->21 gives the {1,2} version of the Thue-Morse sequence A001285, cf. A010060.
%C A245555 The morphism 0->01, 1->12, 2->20 gives the generalized Thue-Morse sequence A071858.
%H A245555 Chai Wah Wu, <a href="/A245555/b245555.txt">Table of n, a(n) for n = 1..10000</a>
%H A245555 <a href="/index/Fi#FIXEDPOINTS">Index entries for sequences that are fixed points of mappings</a>
%F A245555 a(n) = A071858(n+1) + 1. - _Michel Dekking_, Sep 29 2020
%t A245555 Nest[ Function[ l, {Flatten[(l /. {1 -> {1, 2}, 2 -> {2, 3}, 3 -> {3, 1}})] }], {1}, 9]
%o A245555 (PARI) {a(n) = my(v = [1]); if( n<1, 0, while( #v<n, v = concat( vector(#v, i, [[1,2], [2,3], [3,1]] [v[i]]))); v[n])}; /* _Michael Somos_, Aug 05 2014 */
%Y A245555 Cf. A001285, A010060, A092782, A105083, A245553, A245554.
%Y A245555 Essentially the same as A071858.
%K A245555 nonn
%O A245555 1,2
%A A245555 _N. J. A. Sloane_, Aug 03 2014