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A007452
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Expand cos x / exp x and invert nonzero coefficients.
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5
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1, -1, 0, 3, -6, 30, 0, -630, 2520, -22680, 0, 1247400, -7484400, 97297200, 0, -10216206000, 81729648000, -1389404016000, 0, 237588086736000, -2375880867360000, 49893498214560000, 0, -12623055048283680000
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OFFSET
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0,4
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LINKS
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Table of n, a(n) for n=0..23.
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FORMULA
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a(4n+2) = 0, a(n) = (-1)^[n == 1, 4, 7 mod 8] * n!/2^floor(n/2). - Ralf Stephan, Mar 06 2004
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CROSSREFS
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Absolute values are essentially the same as A046981, where zeros are replaced by ones.
Cf. A052277, A007019, A046979, A007415, A009775, A092820.
Sequence in context: A024497 A007228 A096155 * A046981 A065943 A025555
Adjacent sequences: A007449 A007450 A007451 * A007453 A007454 A007455
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KEYWORD
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sign
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AUTHOR
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N. J. A. Sloane.
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STATUS
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approved
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