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 A352842 #20 Aug 16 2022 07:43:58
%S A352842 1,1,11,199,7585,427961,37901851,4526311231,729098029409,
%T A352842 149311985624785,38243144308952971,11913301283967428951,
%U A352842 4445712423354285230401,1954806416110914007773769,1000799932457357582959443035,589931632494798210345741193231
%N A352842 Expansion of e.g.f. exp(Sum_{k>=1} sigma_k(k) * x^k).
%H A352842 Seiichi Manyama, <a href="/A352842/b352842.txt">Table of n, a(n) for n = 0..232</a>
%F A352842 a(0) = 1; a(n) = (n-1)! * Sum_{k=1..n} k * sigma_k(k) * a(n-k)/(n-k)!.
%F A352842 a(n) ~ n! * n^n. - _Vaclav Kotesovec_, Apr 15 2022
%t A352842 nmax = 20; CoefficientList[Series[E^(Sum[DivisorSigma[k, k]*x^k, {k, 1, nmax}]), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Apr 15 2022 *)
%o A352842 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=1, N, sigma(k, k)*x^k))))
%o A352842 (PARI) a(n) = if(n==0, 1, (n-1)!*sum(k=1, n, k*sigma(k, k)*a(n-k)/(n-k)!));
%Y A352842 Cf. A294363, A294361, A294362.
%K A352842 nonn
%O A352842 0,3
%A A352842 _Seiichi Manyama_, Apr 05 2022