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 A352435 #6 Mar 16 2022 16:33:18
%S A352435 1,1,2,7,32,182,1244,9919,90384,926552,10553728,132231446,1807390960,
%T A352435 26762801828,426771821000,7291604699407,132885997278944,
%U A352435 2573145015936096,52756125043795232,1141727892772848248,26009303834699461248,622134297287753003008,15589886235793001142016
%N A352435 a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/2)} binomial(n,2*k+1) * a(k) * a(n-2*k-1).
%F A352435 E.g.f.: 1 / (1 - Sum_{n>=0} a(n) * x^(2*n+1) / (2*n+1)!).
%t A352435 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, 2 k + 1] a[k] a[n - 2 k - 1], {k, 0, Floor[(n - 1)/2]}]; Table[a[n], {n, 0, 22}]
%Y A352435 Cf. A138314, A352436, A352437.
%K A352435 nonn
%O A352435 0,3
%A A352435 _Ilya Gutkovskiy_, Mar 16 2022