a(n) = Sum_{k=0..n} binomial(4*n+1,k) * binomial(3*n-k-1,n-k).

A386939

a(n) = Sum_{k=0..n} binomial(4*n+1,k) * binomial(3*n-k-1,n-k).

Terms

    a(0) =1a(1) =7a(2) =82a(3) =1083a(4) =15086a(5) =216566a(6) =3169636a(7) =47020371a(8) =704497750a(9) =10636206306a(10) =161553957500

External references