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 A330020 #5 Nov 27 2019 12:53:07
%S A330020 1,3,7,49,121,2161,5041,127681,725761,12852001,39916801,2917918081,
%T A330020 6227020801,392423391361,4740319584001,122053759027201,
%U A330020 355687428096001,57808258040332801,121645100408832001,18854997267794688001,289799177540640768001,7306005040298918553601
%N A330020 Expansion of e.g.f. Sum_{k>=1} x^k / (k! * (1 - x^k)^k).
%F A330020 a(n) = n! * Sum_{d|n} (d + n/d - 2)! / (d! * (d - 1)! * (n/d - 1)!).
%t A330020 nmax = 22; CoefficientList[Series[Sum[x^k/(k! (1 - x^k)^k), {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]! // Rest
%t A330020 a[n_] := n! Sum[(d + n/d - 2)!/(d! (d - 1)! (n/d - 1)!), {d, Divisors[n]}]; Table[a[n], {n, 1, 22}]
%Y A330020 Cf. A057625, A157019, A327578, A327579.
%K A330020 nonn
%O A330020 1,2
%A A330020 _Ilya Gutkovskiy_, Nov 27 2019