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A013462
Expansion of e.g.f.: exp(arctan(x)-arctanh(x))=1-4/3!*x^3+160/6!*x^6-1440/7!*x^7...
0
1, 0, 0, -4, 0, 0, 160, -1440, 0, -17920, 691200, -7257600, 3942400, -395366400, 14125363200, -175791616000, 295206912000, -24049778688000, 902471385088000, -13090802909184000, 43911376404480000
OFFSET
0,4
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Exp[ArcTan[x]-ArcTanh[x]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, May 25 2016 *)
CROSSREFS
Sequence in context: A358292 A071608 A013451 * A326862 A222325 A101453
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Definition clarified by Harvey P. Dale, May 25 2016
STATUS
approved