a(n) = Sum_{k=0..n} C(n,k) * (1 + 3^k)^(n-k) * 2^k.
A244760
a(n) = Sum_{k=0..n} C(n,k) * (1 + 3^k)^(n-k) * 2^k.
Terms
- a(0) =1a(1) =4a(2) =24a(3) =232a(4) =3840a(5) =111904a(6) =5785344a(7) =529662592a(8) =85449338880
External references
- oeis: A244760