a(n) = Sum_{k=0..n} binomial(4*n+k-1,k) * binomial(4*n+k,n-k).

A379026

a(n) = Sum_{k=0..n} binomial(4*n+k-1,k) * binomial(4*n+k,n-k).

Terms

    a(0) =1a(1) =8a(2) =136a(3) =2612a(4) =52888a(5) =1103248a(6) =23458756a(7) =505519792a(8) =11001461560a(9) =241240165796

External references