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 A352693 #15 Apr 05 2022 21:20:19
%S A352693 1,1,7,46,455,5406,78172,1312116,25214479,544777183,13080808752,
%T A352693 345471545728,9953804592152,310687941345796,10443489230611052,
%U A352693 376122782541917166,14449157656748079247,589772212576633845886,25488817336672959449725
%N A352693 Expansion of e.g.f. 1 / (1 - Sum_{k>=1} sigma_2(k) * x^k/k!).
%H A352693 Seiichi Manyama, <a href="/A352693/b352693.txt">Table of n, a(n) for n = 0..393</a>
%F A352693 a(0) = 1; a(n) = Sum_{k=1..n} sigma_2(k) * binomial(n,k) * a(n-k).
%o A352693 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-sum(k=1, N, sigma(k, 2)*x^k/k!))))
%o A352693 (PARI) a(n) = if(n==0, 1, sum(k=1, n, sigma(k, 2)*binomial(n, k)*a(n-k)));
%Y A352693 Cf. A340903, A340904.
%Y A352693 Cf. A001157, A320649, A352694.
%K A352693 nonn
%O A352693 0,3
%A A352693 _Seiichi Manyama_, Mar 29 2022