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

A388911

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

Terms

    a(0) =1a(1) =9a(2) =137a(3) =2349a(4) =42433a(5) =789489a(6) =14971001a(7) =287691525a(8) =5582952449a(9) =109163050137

External references