A012074 sech(arcsin(arcsin(x)))=1-1/2!*x^2-3/4!*x^4-69/6!*x^6-3335/8!*x^8...

1, -1, -3, -69, -3335, -289801, -39612939, -7845054541, -2125704833551, -755532171928081, -341044077485199379, -190581499954444336725, -129146418452087275163415, -104328785204254369631603225

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcSin[ArcSin[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Dec 25 2011 *)

Crossrefs

Sequence in context: A012201 A284058 A012096 * A350720 A247031 A037109

Adjacent sequences: A012071 A012072 A012073 * A012075 A012076 A012077

Keyword

sign

Author

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

Status

approved