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A012054
arctan(sin(arctanh(x)))=x-1/3!*x^3+9/5!*x^5-225/7!*x^7+3345/9!*x^9...
0
1, -1, 9, -225, 3345, -893025, -36212775, -20892252225, -3614048241375, -1664630362370625, -584598534985164375, -327627617091486830625, -181787523574523506599375, -131875411531849225343390625
OFFSET
0,3
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[ArcTan[Sin[ArcTanh[x]]], {x, 0, nn}], x]Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jan 23 2013 *)
CROSSREFS
Sequence in context: A074190 A069075 A218659 * A067405 A063386 A063392
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Definition clarified by Harvey P. Dale, Jan 23 2013
STATUS
approved