a(n) = a(n-1)*a(n-2) - 1.

Terms

a(0) =0a(1) =1a(2) =-1a(3) =-2a(4) =1a(5) =-3a(6) =-4a(7) =11a(8) =-45a(9) =-496a(10) =22319a(11) =-11070225a(12) =-247076351776