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 A356437 #14 Aug 07 2022 12:59:05
%S A356437 1,7,77,1946,84754,6202524,636369348,89979720144,16431405256656,
%T A356437 3796658174518560,1077102230236529760,368915006390671969920,
%U A356437 149873555740938949215360,71297150722148582901815040,39244301012876892023553235200
%N A356437 a(n) = n! * Sum_{k=1..n} sigma_k(k)/k.
%F A356437 E.g.f.: -(1/(1-x)) * Sum_{k>0} log(1 - (k*x)^k)/k.
%F A356437 a(n) ~ n! * n^(n-1). - _Vaclav Kotesovec_, Aug 07 2022
%t A356437 Table[n! * Sum[DivisorSigma[k, k]/k, {k, 1, n}], {n, 1, 20}] (* _Vaclav Kotesovec_, Aug 07 2022 *)
%o A356437 (PARI) a(n) = n!*sum(k=1, n, sigma(k, k)/k);
%o A356437 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(-sum(k=1, N, log(1-(k*x)^k)/k)/(1-x)))
%Y A356437 Cf. A023887, A356297, A356436, A356440.
%K A356437 nonn
%O A356437 1,2
%A A356437 _Seiichi Manyama_, Aug 07 2022