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A009486
sin(sin(x)*sin(x)) = 2/2!*x^2 - 8/4!*x^4 - 88/6!*x^6 + 6592/8!*x^8 - ...
2
0, 2, -8, -88, 6592, -251488, 4158592, 551599232, -94759774208, 9549823734272, -506903275563008, -67623197282080768, 30434079688615739392, -6806476994628810661888, 994937886379415577198592
OFFSET
0,2
FORMULA
a(n) = 1/2*sum(k=0..(n-1)/2,(4^(n-2*k)*sum(i=0..2*k+1, (i-2*k-1)^(2*n)*binomial(4*k+2,i)*(-1)^(n-i+k-1)))/(2*k+1)!). - Vladimir Kruchinin, Jun 28 2011
MATHEMATICA
With[{nn=30}, Take[CoefficientList[Series[Sin[Sin[x]^2] , {x, 0, nn}], x] Range[ 0, nn]!, {1, -1, 2}]] (* Harvey P. Dale, Feb 19 2020 *)
PROG
(Maxima)
a(n):=1/2*sum((4^(n-2*k)*sum((i-2*k-1)^(2*n)*binomial(4*k+2, i)*(-1)^(n-i+k-1), i, 0, 2*k+1))/(2*k+1)!, k, 0, (n-1)/2); /* Vladimir Kruchinin, Jun 28 2011 */
CROSSREFS
Sequence in context: A054955 A012299 A012295 * A110384 A153887 A131349
KEYWORD
sign
AUTHOR
EXTENSIONS
Extended with signs by Olivier Gérard, Mar 15 1997
Edited by N. J. A. Sloane, May 31 2008 at the suggestion of R. J. Mathar
Prior Mathematica program replaced by Harvey P. Dale, Feb 19 2020
STATUS
approved