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 A361532 #21 Jun 08 2023 14:02:05
%S A361532 1,1,4,19,118,886,7786,78184,881644,11017108,150966856,2249261356,
%T A361532 36181351504,624658612384,11516406883528,225740649754936,
%U A361532 4686671645814736,102712289940757264,2369128149877075264,57359541280704038128,1454229915957292684576
%N A361532 Expansion of e.g.f. exp((x + x^2/2)/(1-x)).
%F A361532 a(n) = (2*n-1) * a(n-1) - (n-1)*(n-3) * a(n-2) - binomial(n-1,2) * a(n-3) for n > 2.
%F A361532 a(n) ~ 2^(-3/4) * 3^(1/4) * exp(-5/4 + sqrt(6*n) - n) * n^(n - 1/4) * (1 + sqrt(3)/(2*sqrt(2*n))). - _Vaclav Kotesovec_, Mar 20 2023
%t A361532 With[{nn=20},CoefficientList[Series[Exp[(x+x^2/2)/(1-x)],{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Jun 08 2023 *)
%o A361532 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp((x+x^2/2)/(1-x))))
%Y A361532 Cf. A361548, A361557, A361558.
%Y A361532 Cf. A052845, A112242, A185369.
%K A361532 nonn
%O A361532 0,3
%A A361532 _Seiichi Manyama_, Mar 15 2023