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 A356689 #13 Sep 17 2022 08:44:42
%S A356689 1,2,20,19887,4297096180,298028721722131825,
%T A356689 10314430386434427534836297166,
%U A356689 256923580889667624113335512704714686054849,6277101737079381675512518990977258744796239498871290255000
%N A356689 a(n) = n! * Sum_{k=0..n} k^(k*n)/k!.
%H A356689 Seiichi Manyama, <a href="/A356689/b356689.txt">Table of n, a(n) for n = 0..26</a>
%F A356689 E.g.f.: Sum_{k>=0} (k^k * x)^k / (k! * (1 - k^k * x)).
%o A356689 (PARI) a(n) = n!*sum(k=0, n, k^(k*n)/k!);
%o A356689 (PARI) my(N=10, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, (k^k*x)^k/(k!*(1-k^k*x)))))
%Y A356689 Cf. A256016, A356687, A356688.
%Y A356689 Cf. A349886, A356674.
%K A356689 nonn
%O A356689 0,2
%A A356689 _Seiichi Manyama_, Aug 23 2022