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 A341505 #10 Feb 22 2021 07:32:32
%S A341505 1,1,4,14,77,427,3076,23088,205316,1936275,20611750,233576818,
%T A341505 2909340750,38527889389,551372037898,8364582709282,135560933977809,
%U A341505 2320127265064403,42072789623722518,802547153889643250,16118882845967168807,339268639052195731063
%N A341505 E.g.f.: Product_{i>=1, j>=1} 1 / (1 - x^(i*j) / (i*j)!).
%H A341505 Vaclav Kotesovec, <a href="/A341505/b341505.txt">Table of n, a(n) for n = 0..447</a>
%F A341505 E.g.f.: Product_{k>=1} 1 / (1 - x^k / k!)^sigma_0(k).
%F A341505 a(n) ~ c * n!, where c = Product_{k>=2} 1/(1 - 1/k!)^sigma_0(k) = 6.6953800201104498115311861820134227776761182601282551253439990653959... - _Vaclav Kotesovec_, Feb 20 2021
%t A341505 nmax = 21; CoefficientList[Series[Product[1/(1 - x^k/k!)^DivisorSigma[0, k], {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]!
%t A341505 a[n_] := a[n] = If[n == 0, 1, (n - 1)! Sum[Sum[d DivisorSigma[0, d]/(d!)^(k/d), {d, Divisors[k]}] a[n - k]/(n - k)!, {k, 1, n}]]; Table[a[n], {n, 0, 21}]
%Y A341505 Cf. A000005, A005651, A006171, A174661, A318693, A340903, A341506, A341876.
%K A341505 nonn
%O A341505 0,3
%A A341505 _Ilya Gutkovskiy_, Feb 13 2021