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%I #17 Jul 24 2018 02:58:22
%S 1,-2,16,-248,6336,-244480,13409408,-999327488,97590304768,
%T -12120423043072,1867576863899648,-349745166753398784,
%U 78248003933970006016,-20613585750577859067904,6315933020629432945606656
%N Expansion of cos(sin(x))/cosh(x), even terms only.
%H G. C. Greubel, <a href="/A009044/b009044.txt">Table of n, a(n) for n = 0..242</a>
%F a(n) ~ (2*n)! * (-1)^n * cosh(sinh(Pi/2)) * 4^(n+1) / Pi^(2*n+1). - _Vaclav Kotesovec_, Jan 22 2015
%t nn = 20; Table[(CoefficientList[Series[Cos[Sin[x]]*Sech[x], {x, 0, 2*nn}], x] * Range[0, 2*nn]!)[[n]], {n, 1, 2*nn+1, 2}] (* _Vaclav Kotesovec_, Jan 22 2015 *)
%o (PARI) x='x+O('x^50); v=Vec(serlaplace(cos(sin(x))/cosh(x))); vector(#v\2,n,v[2*n-1]) \\ _G. C. Greubel_, Jul 23 2018
%K sign
%O 0,2
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997
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