A009165 Expansion of e.g.f. cosh(tan(x)*sinh(x)) (only even powers).

1, 0, 12, 360, 14672, 947520, 89973312, 11518066560, 1887213285632, 383583690823680, 94596308487109632, 27811060234433710080, 9605125245736932134912, 3848453455438561596456960, 1769620183216433186169372672, 925166579657041497527108075520, 545452011168554618020190985715712

Offset

0,3

Links

Table of n, a(n) for n=0..16.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cosh[Tan[x]*Sinh[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Aug 14 2020 *)

Crossrefs

Sequence in context: A009079 A012379 A012424 * A012627 A012384 A012429

Adjacent sequences: A009162 A009163 A009164 * A009166 A009167 A009168

Keyword

nonn

Author

R. H. Hardin

Extensions

Extended and signs tested by Olivier Gérard, Mar 15 1997

Previous Mathematica program replaced by Harvey P. Dale, Aug 14 2020

a(14)-a(16) from Stefano Spezia, Dec 27 2025

Status

approved