a(0)=a(1)=1, a(2)=3, thereafter a(n) = n*a(n-1)+(n-1)*(n-2)*a(n-2).
A291287
a(0)=a(1)=1, a(2)=3, thereafter a(n) = n*a(n-1)+(n-1)*(n-2)*a(n-2).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =11a(4) =62a(5) =442a(6) =3892a(7) =40504a(8) =487496a(9) =6655688a(10) =101656592a(11) =1717234432a(12) =31789038304a(13) =639932442976
External references
- oeis: A291287