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

A388207

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

Terms

    a(0) =1a(1) =21a(2) =289a(3) =3333a(4) =35073a(5) =350005a(6) =3379489a(7) =31933221a(8) =297326337a(9) =2739788117a(10) =25057889313a(11) =227913373253

External references