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 A356538 #11 Aug 11 2022 08:54:07
%S A356538 1,1,5,27,249,2085,30645,354375,6542865,108554985,2330525925,
%T A356538 45331607475,1288779532425,28889867731725,876160258298325,
%U A356538 25315531795929375,860642393272286625,26527678331237708625,1063065483349950205125,36393649136002135852875
%N A356538 Expansion of e.g.f. Product_{k>0} 1/(1 - (2 * x)^k)^(1/2^k).
%F A356538 a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} A090879(k) * a(n-k)/(n-k)!.
%o A356538 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/prod(k=1, N, (1-(2*x)^k)^(1/2^k))))
%o A356538 (PARI) a090879(n) = sumdiv(n, d, d*2^(n-d));
%o A356538 a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=1, n, v[i+1]=(i-1)!*sum(j=1, i, a090879(j)*v[i-j+1]/(i-j)!)); v;
%Y A356538 Cf. A000041, A006950, A356530, A356540.
%Y A356538 Cf. A090879.
%K A356538 nonn
%O A356538 0,3
%A A356538 _Seiichi Manyama_, Aug 11 2022