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A010050 (2n)!. +0
28
1, 2, 24, 720, 40320, 3628800, 479001600, 87178291200, 20922789888000, 6402373705728000, 2432902008176640000, 1124000727777607680000, 620448401733239439360000, 403291461126605635584000000 (list; graph; listen)
OFFSET

0,2

COMMENT

Denominators in the expansion of cos(x): cos(x) = 1 - x^2/2! + x^4/4! - x^6/6! + x^8/8! - ...

REFERENCES

W. Dunham, Touring the calculus gallery, Amer. Math. Monthly, 112 (2005), 1-19.

I. Newton, De analysi, 1669; reprinted in D. Whiteside, ed., The Mathematical Works of Isaac Newton, vol. 1, Johnson Reprint Co., 1964; see p. 20.

H. B. Dwight, Tables of Integrals and Other Mathematical Data, Macmillan, NY, 1968, p. 88.

LINKS

Eric Weisstein's World of Mathematics, Hyperbolic Cosine

Index entries for related partition-counting sequences

FORMULA

E.g.f. for sequence with alt. signs: arctan(x).

E.g.f. : 1/(1-x^2) (with interpolated zeros). - Paul Barry (pbarry(AT)wit.ie), Sep 14 2004

a(n+1) = a(n)*(2n+1)*(2n+2) = a(n)*A002939(n-1). - Lekraj Beedassy (blekraj(AT)yahoo.com), Apr 29 2005

MATHEMATICA

s=1; lst={s}; Do[s+=(s*=n)*n; AppendTo[lst, s], {n, 1, 5!, 2}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Nov 15 2008]

CROSSREFS

Cf. A000142, A000165, A009445.

Bisection of A005359, |A012251|, A012254, A070734.

Adjacent sequences: A010047 A010048 A010049 this_sequence A010051 A010052 A010053

Sequence in context: A046977 A119699 A093459 this_sequence A012161 A009724 A009396

KEYWORD

nonn,easy

AUTHOR

Joe Keane (jgk(AT)jgk.org)

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Last modified November 3 12:59 EST 2009. Contains 165766 sequences.


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