OFFSET
0,2
MATHEMATICA
With[{nn=34}, Take[CoefficientList[Series[Sech[ArcTanh[x]*ArcTan[x]], {x, 0, nn}], x] Range[0, nn-2]!, {1, -1, 4}]] (* Ray Chandler, Nov 28 2016 *)
CROSSREFS
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved