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

Terms

a(0) =1a(1) =0a(2) =1a(3) =2a(4) =7a(5) =30a(6) =157a(7) =972a(8) =6961a(9) =56660a(10) =516901a(11) =5225670a(12) =57999271a(13) =701216922a(14) =9173819257a(15) =129134686520