G.f.: Sum_{n>=0} (n-2*x)^n * x^n / (1 + n*x - 2*x^2)^n.
A203799
G.f.: Sum_{n>=0} (n-2*x)^n * x^n / (1 + n*x - 2*x^2)^n.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =8a(4) =48a(5) =312a(6) =2280a(7) =18720a(8) =171360a(9) =1733760a(10) =19232640a(11) =232243200a(12) =3033676800a(13) =42631142400a(14) =641383142400
External references
- oeis: A203799