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A009486
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sin(sin(x)*sin(x)) = 2/2!*x^2 - 8/4!*x^4 - 88/6!*x^6 + 6592/8!*x^8 - ...
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2
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0, 2, -8, -88, 6592, -251488, 4158592, 551599232, -94759774208, 9549823734272, -506903275563008, -67623197282080768, 30434079688615739392, -6806476994628810661888, 994937886379415577198592
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OFFSET
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0,2
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LINKS
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FORMULA
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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
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MATHEMATICA
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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 *)
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PROG
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(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 */
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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