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

Terms

a(0) =1a(1) =2a(2) =1a(3) =0a(4) =-1a(5) =-4a(6) =-19a(7) =-110a(8) =-751a(9) =-5898a(10) =-52331a(11) =-517412a(12) =-5639201a(13) =-67153000a(14) =-867349799a(15) =-12075744186a(16) =-180268812991