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 A356542 #8 Aug 11 2022 08:54:24
%S A356542 1,1,4,18,132,900,11160,100800,1809360,25053840,608428800,8610386400,
%T A356542 469291838400,7110609105600,404607162960000,13958116204032000,
%U A356542 821937470818464000,17420311428103584000,2860701872247483264000,60029296274562398784000
%N A356542 Expansion of e.g.f. Product_{k>0} 1/(1 - k! * x^k)^(1/k!).
%F A356542 a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} A356541(k) * a(n-k)/(n-k)!.
%o A356542 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/prod(k=1, N, (1-k!*x^k)^(1/k!))))
%o A356542 (PARI) a356541(n) = sumdiv(n, d, d*d!^(n/d-1));
%o A356542 a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=(i-1)!*sum(j=1, i, a356541(j)*v[i-j+1]/(i-j)!)); v;
%Y A356542 Cf. A209902, A356524, A356541.
%K A356542 nonn
%O A356542 0,3
%A A356542 _Seiichi Manyama_, Aug 11 2022