A012747 cosh(arctanh(x)*cos(x))=1+1/2!*x^2-3/4!*x^4+45/6!*x^6+2457/8!*x^8...

1, 1, -3, 45, 2457, 161625, 20549397, 3457938757, 772773915313, 221864504883633, 79479234590193325, 34768359140993612893, 18241340561609524790601, 11306811847252896133698825

Offset

0,3

Links

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

Mathematica

With[{nn=30}, Take[CoefficientList[Series[Cosh[ArcTanh[x]Cos[x]], {x, 0, nn}], x] Range[ 0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jul 07 2022 *)

Crossrefs

Sequence in context: A163002 A117253 A012833 * A210933 A356519 A027637

Adjacent sequences: A012744 A012745 A012746 * A012748 A012749 A012750

Keyword

sign

Author

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

Status

approved