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 A318250 #7 Aug 22 2018 10:34:40
%S A318250 1,5,20,126,624,6000,36000,428400,3669120,47174400,442713600,
%T A318250 8382528000,81430272000,1556755200000,22666355712000,445916959488000,
%U A318250 6067609067520000,161837779783680000,2317659281473536000,66418224823222272000,1216451004088320000000,31165474724742758400000
%N A318250 a(n) = (n - 1)! * sigma_2(n), where sigma_2(n) = sum of squares of divisors of n (A001157).
%F A318250 E.g.f.: Sum_{k>=1} x^k/(k*(1 - x^k)^2).
%F A318250 E.g.f.: -log(Product_{k>=1} (1 - x^k)^k).
%F A318250 E.g.f.: A(x) = log(B(x)), where B(x) = o.g.f. of A000219.
%F A318250 a(p^k) = (p^(2*k+2) - 1)*(p^k - 1)!/(p^2 - 1), where p is a prime.
%t A318250 Table[(n - 1)! DivisorSigma[2, n], {n, 1, 22}]
%t A318250 nmax = 22; Rest[CoefficientList[Series[Sum[x^k/(k (1 - x^k)^2), {k, 1, nmax}], {x, 0, nmax}], x] Range[0, nmax]!]
%t A318250 nmax = 22; Rest[CoefficientList[Series[-Log[Product[(1 - x^k)^k, {k, 1, nmax}]], {x, 0, nmax}], x] Range[0, nmax]!]
%o A318250 (PARI) a(n) = (n-1)!*sigma(n,2); \\ _Michel Marcus_, Aug 22 2018
%Y A318250 Cf. A000219, A001157, A038048, A318249.
%K A318250 nonn
%O A318250 1,2
%A A318250 _Ilya Gutkovskiy_, Aug 22 2018