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A064335 6(2n)!/(n+2). 1
3, 4, 36, 864, 40320, 3110400, 359251200, 58118860800, 12553673932800, 3492203839488000, 1216451004088320000, 518769566666588160000, 265906457885674045440000, 161316584450642254233600000 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

All terms, except a(0) and a(1), are integer multiples of 6.

LINKS

Harry J. Smith, Table of n, a(n) for n=0,...,100

FORMULA

Representation as n-th moment of a positive function on a positive half-axis, in Maple notation : a(n)=int(x^n*(exp(-sqrt(x))*(-1+sqrt(x)+2/sqrt(x))+x*Ei(-sqrt(x))), x=0..infinity), n=0, 1..., where Ei(y) is the exponential integral. This representation is unique.

PROG

(PARI) { s=6; for (n=0, 100, if (n, s*=2*n*(2*n - 1)); a=s/(n + 2); write("b064335.txt", n, " ", a) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Sep 12 2009]

CROSSREFS

Cf. A060593.

Sequence in context: A042891 A032835 A102920 * A013330 A088168 A032836

Adjacent sequences:  A064332 A064333 A064334 * A064336 A064337 A064338

KEYWORD

nonn

AUTHOR

Karol A. Penson (penson(AT)lptl.jussieu.fr), Sep 13 2001

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Last modified February 14 23:53 EST 2012. Contains 205689 sequences.