OFFSET
1,1
COMMENTS
Equals column 1 of triangle A136635.
FORMULA
a(n) ~ 2^n * 3^(n*(n-1)) / (n-1)!. - Vaclav Kotesovec, Jul 02 2016
MAPLE
MATHEMATICA
Table[n*Binomial[2*3^(n - 1), n], {n, 10}] (* Wesley Ivan Hurt, Apr 29 2014 *)
PROG
(PARI) {a(n)=n*binomial(2*3^(n-1), n)}
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladeta Jovovic and Paul D. Hanna, Jan 15 2008
STATUS
approved