a(n) = Sum_{k=0..n} 3^k * 2^(n-k) * binomial(2*n+1,k) * binomial(2*n-k,n-k).

A386829

a(n) = Sum_{k=0..n} 3^k * 2^(n-k) * binomial(2*n+1,k) * binomial(2*n-k,n-k).

Terms

    a(0) =1a(1) =13a(2) =204a(3) =3457a(4) =61006a(5) =1103598a(6) =20299434a(7) =377871297a(8) =7097430726a(9) =134243202358

External references