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A091669 a(n)=product(2*k-1,k=2..n-1)*2^(n-1)/n!. 0
1, 1, 2, 7, 42, 434, 7812, 248031, 14055090, 1436430198, 267176016828, 91151551074486, 57425477176926180, 67196011936600334340, 146782968474309770332296, 601204690999713530559792879 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..16.

FORMULA

a(n)=2^(n-1)*A005329(n-1)/n!.

MATHEMATICA

Table[QFactorial[n-1, 2] 2^(n-1)/n!, {n, 20}]

CROSSREFS

Sequence in context: A011802 A007065 A005130 * A108042 A152559 A267239

Adjacent sequences:  A091666 A091667 A091668 * A091670 A091671 A091672

KEYWORD

nonn

AUTHOR

Karol A. Penson, Jan 27 2004

STATUS

approved

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Last modified February 20 01:06 EST 2018. Contains 299357 sequences. (Running on oeis4.)