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A012010 arctan(sin(sin(x))) = x - 4/3!*x^3 + 76/5!*x^5 - 3592/7!*x^7 + 317968/9!*x^9 - .... 0
1, -4, 76, -3592, 317968, -45286528, 9459412288, -2724254181760, 1034595588065536, -500961002883890176, 301230818225601928192, -220218226893098691684352, 192355329482117756948647936 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

a(n) appears to be divisible by 2^n, with the other factor -2, 19, -449, 19873, -1415204, 147803317,.... - Ralf Stephan, Aug 14 2013

LINKS

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

MATHEMATICA

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

CROSSREFS

Sequence in context: A012101 A012080 A012047 * A012155 A325214 A118193

Adjacent sequences:  A012007 A012008 A012009 * A012011 A012012 A012013

KEYWORD

sign

AUTHOR

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

STATUS

approved

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Last modified December 5 20:39 EST 2021. Contains 349558 sequences. (Running on oeis4.)