A (1,3) Somos-4 sequence.

Terms

a(0) =1a(1) =-2a(2) =1a(3) =13a(4) =-23a(5) =-242a(6) =-1559a(7) =16273a(8) =-145799a(9) =-4222034a(10) =3164281a(11) =3257872813a(12) =94135157041