a(n) = n*a(n-1) + (n-1)*a(n-2), a(0) = 1, a(1) = 1.
A000255
a(n) = n*a(n-1) + (n-1)*a(n-2), a(0) = 1, a(1) = 1.
Terms
- a(0) =1a(1) =1a(2) =3a(3) =11a(4) =53a(5) =309a(6) =2119a(7) =16687a(8) =148329a(9) =1468457a(10) =16019531a(11) =190899411a(12) =2467007773a(13) =34361893981a(14) =513137616783
External references
- oeis: A000255