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%I #4 Mar 30 2012 18:40:42

%S 1,4,35,240,3003,26880,415701,4435200,79676025,968647680,19535112675,

%T 263472168960,5837993287875,85816649318400,2058476433304725,

%U 32567418416332800,836589039864843825,14112547980410880000

%N A113551(n)/A006882(n).

%C a(n) is to A001700 as n!! is to n!.

%F a(n) = n * (n+2) * ... * ((3*n)-2) / n!!.

%e a(1) = (1)/(1) = 1.

%e a(2) = (2*4)/(2) = 4.

%e a(3) = (3*5*7)/(3*1) = 35.

%e a(4) = (4*6*8*10)/(4*2) = 240.

%e a(5) = (5*7*9*11*13)/(5*3*1) = 3003.

%e a(6) = (6*8*10*12*14*16)/(6*4*2) = 26880.

%Y Cf. A001700, A006882, A113551.

%K easy,nonn

%O 1,2

%A _Jonathan Vos Post_, Apr 10 2007

%E Corrected and extended by _Klaus Brockhaus_, Apr 15 2007