A012564 sec(sinh(x)*arctan(x))=1+12/4!*x^4-120/6!*x^6+15120/8!*x^8...

1, 0, 12, -120, 15120, -1003200, 175323456, -30612097152, 8428742150400, -2694273274447872, 1128666024421563392, -559638290295925823488, 336992041752644836265984, -237186459370976230365020160

Offset

0,3

Links

Table of n, a(n) for n=0..13.

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sec[Sinh[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jul 04 2019 *)

Crossrefs

Sequence in context: A012441 A012373 A012620 * A012442 A262204 A037097

Adjacent sequences: A012561 A012562 A012563 * A012565 A012566 A012567

Keyword

sign

Author

Patrick Demichel (patrick.demichel(AT)hp.com)

Status

approved