a(n) = (n-1)*a(n-1) - a(n-2) + (n-2)*a(n-3) with a(0)=0, a(1)=a(2)=1.
A269450
a(n) = (n-1)*a(n-1) - a(n-2) + (n-2)*a(n-3) with a(0)=0, a(1)=a(2)=1.
Terms
- a(0) =0a(1) =1a(2) =1a(3) =1a(4) =4a(5) =18a(6) =90a(7) =542a(8) =3812a(9) =30584a(10) =275780a(11) =2761524a(12) =30406824a(13) =365153944a(14) =4749732736a(15) =66526393072a(16) =998258318560
External references
- oeis: A269450