A009100 Expansion of e.g.f. cos(x)*cos(tanh(x)), even powers only.

1, -2, 16, -328, 11712, -638720, 49459840, -5159926528, 697030680576, -118233272496128, 24578235697610752, -6139851821419921408, 1813615341438397218816, -624948457889265099014144

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cos[x]*Cos[Tanh[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Oct 07 2015 *)

Prog

(PARI) x='x+O('x^50); v=Vec(serlaplace(cos(x)*cos(tanh(x)))); vector(#v\2, n, v[2*n-1]) \\ G. C. Greubel, Jul 26 2018

Crossrefs

Sequence in context: A282392 A336522 A294039 * A009109 A268560 A275854

Adjacent sequences: A009097 A009098 A009099 * A009101 A009102 A009103

Keyword

sign

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Prior Mathematica program replaced by Harvey P. Dale, Oct 07 2015

Status

approved