a(n) = n*a(n-1) + (n-2)*a(n-2), a(0) = 0, a(1) = 2.
A055790
a(n) = n*a(n-1) + (n-2)*a(n-2), a(0) = 0, a(1) = 2.
Terms
- a(0) =0a(1) =2a(2) =4a(3) =14a(4) =64a(5) =362a(6) =2428a(7) =18806a(8) =165016a(9) =1616786a(10) =17487988a(11) =206918942a(12) =2657907184a(13) =36828901754a(14) =547499510764
External references
- oeis: A055790