A009254 Expansion of exp(tan(x)/cosh(x)).

1, 1, 1, 0, -3, 12, 117, 336, -903, -2096, 111529, 1043328, 687093, -29488704, 320199453, 8894706432, 44530596081, -389860902656, 254346923089, 170568226222080, 2006766293627373, -6327905330549760, -141849542553657147

Offset

0,5

Links

Table of n, a(n) for n=0..22.

Mathematica

With[{nn=30}, CoefficientList[Series[Exp[Tan[x]/Cosh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Mar 07 2018 *)

Crossrefs

Sequence in context: A308144 A320257 A350410 * A133987 A359658 A194506

Adjacent sequences: A009251 A009252 A009253 * A009255 A009256 A009257

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 07 2018

Status

approved