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

A384338

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

Terms

    a(0) =1a(1) =11a(2) =169a(3) =2864a(4) =50857a(5) =928091a(6) =17242900a(7) =324433064a(8) =6162083161a(9) =117893396513

External references