A009058 Expansion of e.g.f. cos(sinh(x))/cos(x), even terms only.

1, 0, -4, -56, -1072, -34368, -1781440, -132000896, -12912385792, -1604411553792, -247155791205376, -46275148760619008, -10352111715031035904, -2727077778568910979072, -835562477291891829882880

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..242

Maple

seq(coeff(series(factorial(n)*cos(sinh(x))/cos(x), x, n+1), x, n), n=0..40, 2); # Muniru A Asiru, Jul 24 2018

Mathematica

With[{nmax = 60}, CoefficientList[Series[Cos[Sinh[x]]/Cos[x], {x, 0, nmax}], x]*Range[0, nmax]!][[1 ;; -1 ;; 2]] (* G. C. Greubel, Jul 23 2018 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(cos(sinh(x))/cos(x))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 23 2018

Crossrefs

Sequence in context: A327199 A358886 A371678 * A276363 A361541 A218309

Adjacent sequences: A009055 A009056 A009057 * A009059 A009060 A009061

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved