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A127488
a(n) = (n^2)!/(2*(n!)).
0
6, 30240, 435891456000, 64630041847212441600000, 258328699159653623241666283438080000000
OFFSET
2,1
FORMULA
a(n) ~ n^(2*n^2 - n + 1/2) / (2 * exp(n*(n-1))). - Vaclav Kotesovec, Oct 26 2017
MATHEMATICA
Table[(n^2)!/(2(n!)), {n, 2, 6}]
KEYWORD
nonn
AUTHOR
Artur Jasinski, Jan 16 2007
STATUS
approved