login
A012224
arctan(arctan(tanh(x)))=x-6/3!*x^3+184/5!*x^5-13584/7!*x^7...
0
1, -6, 184, -13584, 1840768, -397140224, 124961670144, -54024939321344, 30732245464219648, -22258174840910315520, 20000813079319781048320, -21837489688957057049821184, 28476242253811580631861166080
OFFSET
0,2
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[ArcTan[ArcTan[Tanh[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 28 2016 *)
CROSSREFS
Sequence in context: A222887 A012208 A012181 * A274272 A175237 A222335
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
STATUS
approved