A009064 Expansion of e.g.f. cos(sinh(x)/cos(x)), even powers only.

1, -1, -15, -297, -6783, -70609, 18558705, 4027228359, 727421677185, 134584692783455, 26232888936219249, 5245335359878123191, 971782758809341914369, 96545317222649153850767

Offset

0,3

Links

G. C. Greubel, Table of n, a(n) for n = 0..239

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 24 2018 *)

Prog

(PARI) x='x+O('x^60); v=Vec(serlaplace(cos(sinh(x)/cos(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 24 2018

Crossrefs

Sequence in context: A201341 A144349 A375222 * A049381 A051691 A247238

Adjacent sequences: A009061 A009062 A009063 * A009065 A009066 A009067

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Status

approved