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 A352436 #6 Mar 16 2022 16:33:13
%S A352436 1,1,2,6,25,130,810,5882,48822,455922,4730766,53996052,672326226,
%T A352436 9069015409,131742237040,2050468853310,34041605882650,600476252401332,
%U A352436 11215153375288308,221103539006813514,4588413676426217916,99981290070561391848,2282329233032693093114
%N A352436 a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/3)} binomial(n,3*k+1) * a(k) * a(n-3*k-1).
%F A352436 E.g.f.: 1 / (1 - Sum_{n>=0} a(n) * x^(3*n+1) / (3*n+1)!).
%t A352436 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, 3 k + 1] a[k] a[n - 3 k - 1], {k, 0, Floor[(n - 1)/3]}]; Table[a[n], {n, 0, 22}]
%Y A352436 Cf. A351968, A352435, A352437.
%K A352436 nonn
%O A352436 0,3
%A A352436 _Ilya Gutkovskiy_, Mar 16 2022