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A012847 arcsinh(sec(x)*arctanh(x))=x+4/3!*x^3+28/5!*x^5+152/7!*x^7+6928/9!*x^9... 0
1, 4, 28, 152, 6928, 2225408, 348750400, 38567316608, 5024551512320, 2238520490011648, 1265695140964379648, 555587429710072952832, 218348017328527789264896, 124784882666107086189330432 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[ArcSinh[Sec[x]ArcTanh[x]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Apr 16 2019 *)

CROSSREFS

Sequence in context: A272992 A272747 A123520 * A273431 A128721 A273647

Adjacent sequences:  A012844 A012845 A012846 * A012848 A012849 A012850

KEYWORD

nonn

AUTHOR

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

STATUS

approved

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Last modified November 27 07:28 EST 2021. Contains 349365 sequences. (Running on oeis4.)