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A013304 sech(log(x+1)-arctanh(x))=1-3/4!*x^4-90/6!*x^6-4095/8!*x^8... 0
1, 0, -3, -90, -4095, -283500, -28534275, -4001347350, -754083705375, -185224922883000, -57754322803051875, -22343321962162451250, -10514758311176393649375, -5917397284663573271062500 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

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

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sech[Log[x+1]-ArcTanh[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Jun 06 2020 *)

CROSSREFS

Sequence in context: A103305 A097235 A047686 * A013298 A013302 A013303

Adjacent sequences:  A013301 A013302 A013303 * A013305 A013306 A013307

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified May 17 23:07 EDT 2022. Contains 353779 sequences. (Running on oeis4.)