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A012681 cos(tanh(x)*arctan(x))=1-12/4!*x^4+480/6!*x^6-25200/8!*x^8... 0
1, 0, -12, 480, -25200, 1789440, -165502656, 18976409088, -2521802100480, 337469315481600, -20084172331338752, -21802197506685280256, 22192552544232587431936, -18125174754251391091998720 (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[Cos[Tanh[x]ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, May 23 2016 *)

CROSSREFS

Sequence in context: A012687 A012467 A009083 * A009168 A012460 A012685

Adjacent sequences:  A012678 A012679 A012680 * A012682 A012683 A012684

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified November 28 05:17 EST 2020. Contains 338699 sequences. (Running on oeis4.)