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A012747
cosh(arctanh(x)*cos(x))=1+1/2!*x^2-3/4!*x^4+45/6!*x^6+2457/8!*x^8...
0
1, 1, -3, 45, 2457, 161625, 20549397, 3457938757, 772773915313, 221864504883633, 79479234590193325, 34768359140993612893, 18241340561609524790601, 11306811847252896133698825
OFFSET
0,3
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
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved