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 A343350 #9 Apr 12 2021 12:13:14 %S A343350 1,1,6,31,171,921,5031,27281,148101,801901,4336902,23415777,126254962, %T A343350 679805112,3655679442,19634501447,105334380517,564471596667, %U A343350 3021754455157,16160029793032,86339725851558,460874548444683,2457961986888773,13097958657023523,69740119667456018 %N A343350 Expansion of Product_{k>=1} 1 / (1 - x^k)^(5^(k-1)). %F A343350 a(n) ~ exp(2*sqrt(n/5) - 1/10 + c/5) * 5^(n - 1/4) / (2*sqrt(Pi)*n^(3/4)), where c = Sum_{j>=2} 1/(j * (5^(j-1) - 1)). - _Vaclav Kotesovec_, Apr 12 2021 %p A343350 a:= proc(n) option remember; `if`(n=0, 1, add(a(n-j)*add( %p A343350 d*5^(d-1), d=numtheory[divisors](j)), j=1..n)/n) %p A343350 end: %p A343350 seq(a(n), n=0..24); # _Alois P. Heinz_, Apr 12 2021 %t A343350 nmax = 24; CoefficientList[Series[Product[1/(1 - x^k)^(5^(k - 1)), {k, 1, nmax}], {x, 0, nmax}], x] %t A343350 a[n_] := a[n] = If[n == 0, 1, (1/n) Sum[Sum[d 5^(d - 1), {d, Divisors[k]}] a[n - k], {k, 1, n}]]; Table[a[n], {n, 0, 24}] %Y A343350 Cf. A034691, A104460, A144069, A343349, A343351, A343352, A343353, A343354, A343355. %K A343350 nonn %O A343350 0,3 %A A343350 _Ilya Gutkovskiy_, Apr 12 2021