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 A329361 #5 Nov 13 2019 08:18:03
%S A329361 0,1,4,10,21,43,88,177,356,714,1429,2860,5722,11445,22891,45784,91569,
%T A329361 183139,366280,732562,1465125,2930252,5860505,11721011,23442024,
%U A329361 46884049,93768100,187536202,375072405,750144811,1500289624,3000579249,6001158499,12002317000
%N A329361 a(n) = Sum_{i = 1..n} 2^(n - i) * A000002(i).
%F A329361 a(n + 1) = A000002(n) + 2 a(n).
%e A329361 The first 5 terms of A000002 are {1, 2, 2, 1, 1}, so a(5) = 2^4 * 1 + 2^3 * 2 + 2^2 * 2 + 2^1 * 1 + 2^0 * 1 = 43.
%t A329361 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 A329361 kol[n_Integer]:=If[n==0,{},Nest[kolagrow,{1},n-1]];
%t A329361 Table[FromDigits[kol[n],2],{n,0,30}]
%Y A329361 Cf. A000002, A054353, A088568, A288605, A296658, A329315, A329316, A329355, A329356, A329360, A329362.
%K A329361 nonn
%O A329361 0,3
%A A329361 _Gus Wiseman_, Nov 12 2019