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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
OFFSET
0,3
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
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved