a(0)=1, a(1)=2, thereafter a(n) = n*a(n-1)+(n-1)*(n-2)*a(n-2).

A291286

a(0)=1, a(1)=2, thereafter a(n) = n*a(n-1)+(n-1)*(n-2)*a(n-2).

Terms

    a(0) =1a(1) =2a(2) =4a(3) =16a(4) =88a(5) =632a(6) =5552a(7) =57824a(8) =695776a(9) =9500128a(10) =145097152a(11) =2451080192a(12) =45373649024a(13) =913400022656

External references