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A012206 sinh(arctan(arctan(x)))=x-3/3!*x^3+49/5!*x^5-1859/7!*x^7+119617/9!*x^9... 0
1, -3, 49, -1859, 119617, -10283171, 678311217, 246695568861, -270153706006015, 221300400903581245, -191103844337252819535, 185242544952868387351165, -204711474044267911803243455 (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[Sinh[ArcTan[ArcTan[x]]], {x, 0, nn}], x] Range[0, nn-1]!, {2, -1, 2}]] (* Ray Chandler, Nov 28 2016 *)

CROSSREFS

Sequence in context: A012199 A300990 A062961 * A012094 A012059 A012166

Adjacent sequences:  A012203 A012204 A012205 * A012207 A012208 A012209

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified October 20 05:51 EDT 2020. Contains 337897 sequences. (Running on oeis4.)