OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..242
FORMULA
a(n) ~ (2*n)! * (-1)^n * cosh(sinh(Pi/2)) * 4^(n+1) / Pi^(2*n+1). - Vaclav Kotesovec, Jan 22 2015
MATHEMATICA
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 *)
PROG
(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
CROSSREFS
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
STATUS
approved