A009292 Expansion of exp(x)/cos(tanh(x)).

1, 1, 2, 4, 4, -4, -32, -104, 400, 5392, 3680, -167936, -719168, 1592384, 45313024, 401669248, -1201882880, -50456008448, -190738937344, 2742470413312, 41876315935744, 310319594802176, -3729103532367872, -116183782320392192

Offset

0,3

Links

Table of n, a(n) for n=0..23.

Mathematica

With[{nn=30}, CoefficientList[Series[Exp[x]/Cos[Tanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 23 2019 *)

Crossrefs

Sequence in context: A291780 A070529 A009145 * A009622 A232845 A269300

Adjacent sequences: A009289 A009290 A009291 * A009293 A009294 A009295

Keyword

sign,easy

Author

R. H. Hardin

Extensions

Extended with signs by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, Mar 23 2019

Status

approved