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 A336666 #5 Jul 30 2020 22:49:46
%S A336666 1,1,10,1839,10386076,2920439606255,61647526987008365796,
%T A336666 138198647831589723000626151799,
%U A336666 44295532378421071881332203441924537230328,2630596041328098180368767727753901255310559993154210399,36407288356000016897632843477214290941136877077516693440464220432175060
%N A336666 a(n) = (n!)^n * [x^n] 1 / (Sum_{k>=0} (-x)^k / (k!)^n)^n.
%t A336666 Table[(n!)^n SeriesCoefficient[1/Sum[(-x)^k/(k!)^n, {k, 0, n}]^n, {x, 0, n}], {n, 0, 10}]
%Y A336666 Cf. A212806, A245398, A336665.
%K A336666 nonn
%O A336666 0,3
%A A336666 _Ilya Gutkovskiy_, Jul 29 2020