a(n) = Sum_{k=0..n} binomial(5*n+1,k) * binomial(5*n-k,n-k).

A386898

a(n) = Sum_{k=0..n} binomial(5*n+1,k) * binomial(5*n-k,n-k).

Terms

    a(0) =1a(1) =11a(2) =199a(3) =4031a(4) =85919a(5) =1885311a(6) =42154111a(7) =955020287a(8) =21847988735a(9) =503573013503

External references