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 A009233 #29 Apr 11 2022 16:38:32
%S A009233 1,2,16,246,5944,202330,9099564,517447126,36048776656,3003924569778,
%T A009233 293835907664980,33232296062419630,4291773869167401720,
%U A009233 626311538509296801226,102365694283336181089084,18595053487766135171539590,3729223211361742071603266464
%N A009233 Expansion of e.g.f. exp(sinh(x)*x) (even powers only).
%F A009233 a(0) = 1; a(n) = 2 * Sum_{k=1..n} binomial(2*n-1,2*k-1) * k * a(n-k). - _Ilya Gutkovskiy_, Mar 10 2022
%t A009233 With[{nn=30},Take[CoefficientList[Series[Exp[Sinh[x]*x],{x,0,nn}],x] Range[0,nn]!,{1,-1,2}]] (* _Harvey P. Dale_, Jul 31 2020 *)
%o A009233 (PARI) my(x='x+O('x^40), v=Vec(serlaplace(exp(sinh(x)*x)))); vector(#v\2, k, v[2*k-1]) \\ _Michel Marcus_, Mar 10 2022
%Y A009233 Cf. A009214, A352254.
%K A009233 nonn
%O A009233 0,2
%A A009233 _R. H. Hardin_
%E A009233 Extended and signs tested by _Olivier Gérard_, Mar 15 1997
%E A009233 Previous Mathematica program replaced by _Harvey P. Dale_, Jul 31 2020