a(n) = Sum_{k=0..n} 3^k * binomial(n+2,k+2) * binomial(2*k+4,k+4).
A387310
a(n) = Sum_{k=0..n} 3^k * binomial(n+2,k+2) * binomial(2*k+4,k+4).
Terms
- a(0) =1a(1) =21a(2) =330a(3) =4690a(4) =63690a(5) =844662a(6) =11052496a(7) =143462592a(8) =1852852365a(9) =23853938185a(10) =306473670822
External references
- oeis: A387310