a(n) = [x^n] (Sum_{k=0..n} (k+1)!*x^k)/(Sum_{k=0..n} (k+1)!*(-x)^k).
A303566
a(n) = [x^n] (Sum_{k=0..n} (k+1)!*x^k)/(Sum_{k=0..n} (k+1)!*(-x)^k).
Terms
- a(0) =1a(1) =4a(2) =8a(3) =40a(4) =128a(5) =1168a(6) =4448a(7) =66400a(8) =268544a(9) =6124480a(10) =25118336a(11) =827294848a(12) =3386501120a(13) =153439657216a(14) =624706655744
External references
- oeis: A303566