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

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =17a(5) =73a(6) =382a(7) =2365a(8) =16937a(9) =137861a(10) =1257686a(11) =12714721a(12) =141119617a(13) =1706150125a(14) =22321071242a(15) =314201147513