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 A330255 #5 Dec 07 2019 08:15:28
%S A330255 1,13,361,21841,1814401,260124481,43589145601,11333696774401,
%T A330255 3210079038566401,1317822591538252801,562000363888803840001,
%U A330255 336953340897297630105601,201645730563302817792000001,165147853334842304408401920001,132994909752412012763531673600001
%N A330255 Expansion of e.g.f. Sum_{k>=1} (cosh(x^k) - 1) (even powers only).
%F A330255 E.g.f.: Sum_{k>=1} x^(2*k) / ((2*k)! * (1 - x^(2*k))) (even powers only).
%F A330255 a(n) = (2*n)! * Sum_{d|n} 1 / (2*d)!.
%t A330255 nmax = 15; Table[(CoefficientList[Series[Sum[Cosh[x^k] - 1, {k, 1, nmax}], {x, 0, 2 nmax}], x] Range[0, 2 nmax]!)[[n]], {n, 1, 2 nmax + 1, 2}] // Rest
%t A330255 Table[(2 n)! DivisorSum[n, 1/(2 #)! &], {n, 1, 15}]
%Y A330255 Cf. A057625, A132958, A176474, A330254.
%K A330255 nonn
%O A330255 1,2
%A A330255 _Ilya Gutkovskiy_, Dec 07 2019