A009161 Expansion of cosh(tan(x))/exp(x).

1, -1, 2, -4, 16, -56, 328, -1576, 11712, -70912, 638720, -4668544, 49459840, -423673472, 5159926528, -50674728448, 697030680576, -7717401038848, 118233272496128, -1456461190426624, 24578235697610752, -333308651379949568

Offset

0,3

Links

Vincenzo Librandi, Table of n, a(n) for n = 0..200

Mathematica

With[{nn=30}, CoefficientList[Series[Cosh[Tan[x]]/Exp[x], {x, 0, nn}], x] Range[ 0, nn]!] (* Harvey P. Dale, Apr 08 2014 *)

Crossrefs

Sequence in context: A153957 A068789 A009624 * A009290 A235459 A081919

Adjacent sequences: A009158 A009159 A009160 * A009162 A009163 A009164

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Mathematica program replaced by Harvey P. Dale, Apr 08 2014

Status

approved