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 A336249 #10 Jul 14 2020 21:39:50
%S A336249 1,2,7,172,79745,1375363126,1445639634946657,136511607703654177490168,
%T A336249 1597074319746489837872943936307201,
%U A336249 3049096207067719868011671739966873049880826186,1209808678412717193052533393657339738066086793611743000000001
%N A336249 a(n) = (n!)^n * Sum_{k=0..n} 1 / ((k!)^n * (n-k)!).
%F A336249 a(n) = (n!)^n * [x^n] exp(x) * Sum_{k>=0} x^k / (k!)^n.
%F A336249 a(n) ~ (2*Pi)^((n-1)/2) * n^(n^2 - n/2 + 1/2) / exp(n*(n-1) - 1/12). - _Vaclav Kotesovec_, Jul 14 2020
%t A336249 Table[(n!)^n Sum[1/((k!)^n (n - k)!), {k, 0, n}], {n, 0, 10}]
%t A336249 Table[(n!)^n SeriesCoefficient[Exp[x] Sum[x^k/(k!)^n, {k, 0, n}], {x, 0, n}], {n, 0, 10}]
%o A336249 (PARI) a(n) = (n!)^n * sum(k=0, n, 1 / ((k!)^n * (n-k)!)); \\ _Michel Marcus_, Jul 14 2020
%Y A336249 Cf. A000079, A002720, A036740, A119400.
%K A336249 nonn
%O A336249 0,2
%A A336249 _Ilya Gutkovskiy_, Jul 14 2020