a(n) = 2*binomial(9*n+6,n)/(3*n+2).

A234509

a(n) = 2*binomial(9*n+6,n)/(3*n+2).

Terms

    a(0) =1a(1) =6a(2) =69a(3) =992a(4) =15990a(5) =276360a(6) =5006386a(7) =93817152a(8) =1803606255a(9) =35373572460a(10) =704995403541

External references