A012797 arcsinh(sec(x)*tan(x))=x+4/3!*x^3+20/5!*x^5-296/7!*x^7-13360/9!*x^9...

1, 4, 20, -296, -13360, 1256704, 189575360, -11506868096, -7128426008320, 49808403426304, 682296985566233600, 90438749300061435904, -128380014279650042490880, -53104829106323270490423296

Offset

0,2

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[ArcSinh[Sec[x]Tan[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Sep 23 2014 *)

Crossrefs

Sequence in context: A053400 A362259 A120599 * A342907 A358544 A167002

Adjacent sequences: A012794 A012795 A012796 * A012798 A012799 A012800

Keyword

sign

Author

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

Status

approved