OFFSET
0,3
FORMULA
a(n) = (n+2)!*(n+3)!*...*(2n)!/(2!*3!*...*n!) = A000178(2n)/(A000178(n)*A000178(n+1)) = A079478(n)/A000142(n+1).
a(n) ~ A * 2^(2*n^2 + 2*n - 7/12) * n^(n^2 - n - 23/12) / (Pi * exp(3*n^2/2 - n + 1/12)), where A = A074962 = 1.2824271291... is the Glaisher-Kinkelin constant. - Vaclav Kotesovec, Jul 10 2015
EXAMPLE
a(3) = 1!*2!*3!*4!*5!*6!/(1!*2!*3!*1!*2!*3!*4!) = 24883200/(12*288) = 7200.
MAPLE
seq(mul(mul(k+j, j=1..n), k=2..n), n=0..8); # Zerinvary Lajos, Jun 01 2007
CROSSREFS
KEYWORD
nonn
AUTHOR
Henry Bottomley, May 14 2005
STATUS
approved