A (4,-3) Somos-4 sequence.

Terms

a(0) =1a(1) =-1a(2) =-7a(3) =-31a(4) =-23a(5) =2239a(6) =39889a(7) =603521a(8) =-27466831a(9) =-2445382081a(10) =-204734091383