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A012203 E.g.f.: exp(arctan(arctan(x))) = 1+x+1/2!*x^2-3/3!*x^3-15/4!*x^4+49/5!*x^5... 1
1, 1, 1, -3, -15, 49, 609, -1859, -48031, 119617, 6247681, -10283171, -1214813487, 678311217, 330587407201, 246695568861, -120086685689663, -270153706006015, 56186566871496961, 221300400903581245 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
MATHEMATICA
With[{nn=20}, CoefficientList[Series[Exp[ArcTan[ArcTan[x]]], {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Aug 14 2014 *)
CROSSREFS
Sequence in context: A124161 A089580 A034564 * A112586 A043005 A165746
KEYWORD
sign
AUTHOR
Patrick Demichel (patrick.demichel(AT)hp.com)
EXTENSIONS
Definition edited and clarified by Harvey P. Dale, Aug 14 2014
STATUS
approved

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Last modified February 22 15:38 EST 2024. Contains 370256 sequences. (Running on oeis4.)