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A013179
cos(arctanh(x)+arctan(x))=1-4/2!*x^2+16/4!*x^4-640/6!*x^6+21760/8!*x^8...
0
1, -4, 16, -640, 21760, -2291200, 223436800, -44438118400, 8725110784000, -2796896567296000, 926039081943040000, -435519369139978240000, 218626979887002419200000, -141711151230417633280000000
OFFSET
0,2
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Cos[ArcTanh[x]+ArcTan[x]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Ray Chandler, Nov 29 2016 *)
CROSSREFS
Sequence in context: A013001 A373739 A218644 * A144177 A300315 A361196
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved