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

A370101

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

Terms

    a(0) =1a(1) =7a(2) =97a(3) =1519a(4) =25089a(5) =427007a(6) =7408897a(7) =130287871a(8) =2313945089a(9) =41409732607a(10) =745530884097

External references