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 A375589 #9 Aug 20 2024 09:14:17
%S A375589 1,0,0,0,24,0,0,2520,40320,0,604800,39916800,479001600,259459200,
%T A375589 50854003200,1961511552000,21097146470400,88921857024000,
%U A375589 8002967132160000,243459152346009600,2642401903325184000,38318206628782080000,2435557926202232832000
%N A375589 Expansion of e.g.f. 1 / (1 + x - x * exp(x^3)).
%F A375589 a(n) = n! * Sum_{k=0..floor(n/3)} (n-3*k)! * Stirling2(k,n-3*k)/k!.
%o A375589 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1+x-x*exp(x^3))))
%o A375589 (PARI) a(n) = n!*sum(k=0, n\3, (n-3*k)!*stirling(k, n-3*k, 2)/k!);
%Y A375589 Cf. A052848, A375588.
%Y A375589 Cf. A357967, A375562.
%K A375589 nonn
%O A375589 0,5
%A A375589 _Seiichi Manyama_, Aug 19 2024