a(n)=4*(a(n-1)a(n-3)-a(n-2)^2)/a(n-4), a(1)=a(2)=a(3)=1, a(4)=-4.

A160567

a(n)=4*(a(n-1)a(n-3)-a(n-2)^2)/a(n-4), a(1)=a(2)=a(3)=1, a(4)=-4.

Terms

    a(0) =1a(1) =1a(2) =1a(3) =-4a(4) =-20a(5) =-144a(6) =704a(7) =34816a(8) =1101824a(9) =12124160a(10) =-4499439616a(11) =-586464362496

External references