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A012202 sech(arctan(arcsin(x)))=1-1/2!*x^2+9/4!*x^4-249/6!*x^6+11953/8!*x^8... 0
1, -1, 9, -249, 11953, -992401, 115133433, -19289685193, 4104153335777, -1154213252748193, 390283459641717353, -165544701587974757145, 81456402896849322863505, -48584594120969426596224305 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..13.

MATHEMATICA

With[{nn=30}, Take[CoefficientList[Series[Sech[ArcTan[ArcSin[x]]], {x, 0, nn}], x] Range[0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Apr 08 2018 *)

CROSSREFS

Sequence in context: A161159 A300757 A289551 * A012098 A012072 A007408

Adjacent sequences:  A012199 A012200 A012201 * A012203 A012204 A012205

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified August 9 06:42 EDT 2022. Contains 356017 sequences. (Running on oeis4.)