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 A337187 #8 Jan 29 2021 10:29:38
%S A337187 1,1,2,3,7,19,63,229,955,4407,22445,124249,746003,4821287,33394193,
%T A337187 246652725,1935828995,16086138151,141100295557,1302780182449,
%U A337187 12630092274099,128275445380247,1362029496267529,15090795795916493,174167341456580947,2090520625244752407
%N A337187 a(n) = 1 + Sum_{k=0..n-2} binomial(n-2,k) * a(k) * a(n-k-2).
%F A337187 E.g.f. A(x) satisfies: A''(x) = exp(x) + A(x)^2.
%t A337187 a[n_] := a[n] = 1 + Sum[Binomial[n - 2, k] a[k] a[n - k - 2], {k, 0, n - 2}]; Table[a[n], {n, 0, 25}]
%Y A337187 Cf. A007558, A054687, A090344.
%K A337187 nonn
%O A337187 0,3
%A A337187 _Ilya Gutkovskiy_, Jan 29 2021