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 A329360 #4 Nov 13 2019 08:18:10
%S A329360 0,1,12,122,1221,12211,122112,1221121,12211212,122112122,1221121221,
%T A329360 12211212212,122112122122,1221121221221,12211212212211,
%U A329360 122112122122112,1221121221221121,12211212212211211,122112122122112112,1221121221221121122,12211212212211211221
%N A329360 The decimal expansion of a(n) is the first n terms of A000002.
%t A329360 kolagrow[q_]:=If[Length[q]<2,Take[{1,2},Length[q]+1],Append[q,Switch[{q[[Length[Split[q]]]],q[[-2]],Last[q]},{1,1,1},0,{1,1,2},1,{1,2,1},2,{1,2,2},0,{2,1,1},2,{2,1,2},2,{2,2,1},1,{2,2,2},1]]]
%t A329360 kol[n_Integer]:=If[n==0,{},Nest[kolagrow,{1},n-1]];
%t A329360 Table[FromDigits[kol[n]],{n,0,30}]
%Y A329360 Cf. A000002, A054353, A088568, A288605, A296658, A329315, A329316, A329355, A329356, A329361, A329362.
%K A329360 nonn,base
%O A329360 0,3
%A A329360 _Gus Wiseman_, Nov 12 2019