a(n) = (0^n + 4^n * binomial(2*n,n))/2.

A098402

a(n) = (0^n + 4^n * binomial(2*n,n))/2.

Terms

    a(0) =1a(1) =4a(2) =48a(3) =640a(4) =8960a(5) =129024a(6) =1892352a(7) =28114944a(8) =421724160a(9) =6372720640a(10) =96865353728

External references