a(n) = Sum_{k=0..n} binomial(3*n+2,k) * binomial(3*n-k,n-k).

A386844

a(n) = Sum_{k=0..n} binomial(3*n+2,k) * binomial(3*n-k,n-k).

Terms

    a(0) =1a(1) =8a(2) =83a(3) =942a(4) =11177a(5) =136164a(6) =1688031a(7) =21187546a(8) =268409813a(9) =3424751568a(10) =43948343243a(11) =566607282118

External references