a(n) = Sum_{k=0..n} binomial(4*n+1,k) * binomial(2*n-k-1,n-k).

A386938

a(n) = Sum_{k=0..n} binomial(4*n+1,k) * binomial(2*n-k-1,n-k).

Terms

    a(0) =1a(1) =6a(2) =57a(3) =608a(4) =6835a(5) =79170a(6) =934892a(7) =11189568a(8) =135263799a(9) =1647649850a(10) =20191754297a(11) =248664799344

External references