A012644 - OEIS

A012644

sec(arcsinh(x)*cos(x))=1+1/2!*x^2-11/4!*x^4-35/6!*x^6+7817/8!*x^8...

1, 1, -11, -35, 7817, -79975, -36304963, 2699226933, 396427182993, -87651048858959, -16569660529400315, 10430924939842521613, -942407687412636958951, -611722217603320514811575

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OFFSET

0,3

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sec[ArcSinh[x]Cos[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jun 16 2021 *)

CROSSREFS

Sequence in context: A217336 A123749 A159493 * A138893 A243151 A225130

Adjacent sequences: A012641 A012642 A012643 * A012645 A012646 A012647

KEYWORD

sign

AUTHOR

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

STATUS

approved