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 A330517 #5 Dec 17 2019 08:41:29
%S A330517 1,-1,-7,-241,-4495,-652801,-15004375,-7047990769,1597056262625,
%T A330517 -360304327144321,286464442762907225,560117092794518159,
%U A330517 78257061390674957994065,5684812583023438995911039,45666128878264725133259682185
%N A330517 Expansion of e.g.f. Product_{k>=1} sech(x^k) (even powers only).
%t A330517 nmax = 14; Table[(CoefficientList[Series[Product[Sech[x^k], {k, 1, nmax}], {x, 0, 2 nmax}], x] Range[0, 2 nmax]!)[[n]], {n, 1, 2 nmax + 1, 2}]
%Y A330517 Cf. A000364, A203716, A229263, A270294, A270662, A270663, A270664, A270665, A270666, A330514, A330515, A330516.
%K A330517 sign
%O A330517 0,3
%A A330517 _Ilya Gutkovskiy_, Dec 17 2019