OFFSET
0,2
FORMULA
a(n) = 2*binomial(3n,n) - binomial(2n,n).
MAPLE
A225050:=n->2*binomial(3*n, n)-binomial(2*n, n); seq(A225050(n), n=0..30); # Wesley Ivan Hurt, May 10 2014
MATHEMATICA
Table[2*Binomial[3 n, n] - Binomial[2 n, n], {n, 30}]
PROG
(PARI) a(n)=2*binomial(3*n, n)-binomial(2*n, n) \\ Charles R Greathouse IV, Apr 26 2013
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Ravichandran Subramanian, Apr 25 2013
STATUS
approved