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A012207 arcsinh(arctan(arctan(x)))=x-5/3!*x^3+137/5!*x^5-9141/7!*x^7... 0
1, -5, 137, -9141, 1130993, -225155941, 66037540345, -26862446793685, 14500070037397089, -10041538909269213637, 8686453887771982767337, -9185311291945403768547829, 11662015255583014905028727633 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..12.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[ArcSinh[ArcTan[ArcTan[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Harvey P. Dale, Jul 16 2013 *)

CROSSREFS

Sequence in context: A159546 A012215 A012142 * A192640 A192641 A192642

Adjacent sequences:  A012204 A012205 A012206 * A012208 A012209 A012210

KEYWORD

sign

AUTHOR

Patrick Demichel (patrick.demichel(AT)hp.com)

EXTENSIONS

Definition clarified by Harvey P. Dale, Jul 16 2013

STATUS

approved

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Last modified October 28 10:46 EDT 2020. Contains 338054 sequences. (Running on oeis4.)