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A012841
sin(sec(x)*arctanh(x))=x+4/3!*x^3+20/5!*x^5-1024/7!*x^7-147568/9!*x^9...
0
1, 4, 20, -1024, -147568, -19148736, -2934842560, -551525234688, -127249126657792, -35789287036394496, -12158191126869847040, -4941201795126314303488, -2379230211581147229286400
OFFSET
0,2
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Sin[Sec[x]ArcTanh[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Feb 15 2022 *)
CROSSREFS
Sequence in context: A160703 A132511 A144989 * A074195 A376049 A332867
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved