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 A302584 #8 Jun 08 2019 08:30:49
%S A302584 1,1,5,36,357,4500,68857,1239504,25661545,600655824,15684383021,
%T A302584 452001644864,14249852124365,487836995500608,18022519535240417,
%U A302584 714658089577017600,30275849571771536977,1364687729891761740032,65213822241378992547925,3293203845745202062590976
%N A302584 a(n) = n! * [x^n] exp(n*x)/cos(x).
%H A302584 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%F A302584 a(n) ~ n^n / cos(1). - _Vaclav Kotesovec_, Jun 08 2019
%t A302584 Table[n! SeriesCoefficient[Exp[n x]/Cos[x], {x, 0, n}], {n, 0, 19}]
%t A302584 Table[(2 I)^n EulerE[n, (1 - I n)/2], {n, 0, 19}]
%Y A302584 Cf. A000364, A003701, A062024, A115415, A115416, A302583, A302585, A302586, A302587.
%K A302584 nonn
%O A302584 0,3
%A A302584 _Ilya Gutkovskiy_, Apr 10 2018