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 A352437 #5 Mar 16 2022 16:33:06
%S A352437 1,1,2,6,24,121,732,5166,41664,378002,3810532,42254256,511145184,
%T A352437 6698543286,94536850576,1429503114816,23056734645504,395129481418584,
%U A352437 7169760547544240,137325429039660432,2768685793537965504,58611883690279194361,1299873446056852916876
%N A352437 a(0) = 1; a(n) = Sum_{k=0..floor((n-1)/4)} binomial(n,4*k+1) * a(k) * a(n-4*k-1).
%F A352437 E.g.f.: 1 / (1 - Sum_{n>=0} a(n) * x^(4*n+1) / (4*n+1)!).
%t A352437 a[0] = 1; a[n_] := a[n] = Sum[Binomial[n, 4 k + 1] a[k] a[n - 4 k - 1], {k, 0, Floor[(n - 1)/4]}]; Table[a[n], {n, 0, 22}]
%Y A352437 Cf. A351969, A352435, A352436.
%K A352437 nonn
%O A352437 0,3
%A A352437 _Ilya Gutkovskiy_, Mar 16 2022