A009688 Expansion of tan(sinh(x)/cos(x)).

1, 6, 132, 6888, 631120, 88901472, 17815778112, 4813349520000, 1685527674636544, 742370072201602560, 401601528167832511488, 261760691714482869528576, 202316143535276408972627968

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Tan[Sinh[x]/Cos[x]], {x, 0, nn}], x] Range[ 0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Mar 20 2023 *)

Crossrefs

Sequence in context: A174250 A277305 A328889 * A132872 A152289 A015503

Adjacent sequences: A009685 A009686 A009687 * A009689 A009690 A009691

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested Mar 15 1997 by Olivier Gérard.

Previous Mathematica program replaced by Harvey P. Dale, Mar 20 2023

Status

approved