%I #13 May 02 2018 04:39:23
%S 1,2,2,10,18,202,418,8762,18546,648842,1361090,72858394,150831762,
%T 11533704106,23631529186,2447950210490,4980921068466,671176131216458,
%U 1359534955872002,230971485534437722,466475222145987282,97492025362288590058,196500782158151756578
%N a(n) = [x^n] (Sum_{k=0..n} k!*x^k)/(Sum_{k=0..n} k!*(-x)^k).
%H Seiichi Manyama, <a href="/A303565/b303565.txt">Table of n, a(n) for n = 0..450</a>
%F a(n) ~ 4*(n-1)! if n is even and a(n) ~ 2*n! if n is odd. - _Vaclav Kotesovec_, May 02 2018
%o (PARI) N=66; x='x+O('x^N); Vec(sum(k=0, N, k!*x^k)/sum(k=0, N, k!*(-x)^k))
%Y Cf. A303566.
%K nonn
%O 0,2
%A _Seiichi Manyama_, Apr 26 2018