A Somos-4 variant.

Terms

a(0) =1a(1) =-1a(2) =-5a(3) =-4a(4) =29a(5) =129a(6) =-65a(7) =-3689a(8) =-16264a(9) =113689a(10) =2382785a(11) =7001471a(12) =-398035821a(13) =-7911171596a(14) =43244638645