a(n) = a(n-4)*a(n-3) + a(n-4)*a(n-2) + a(n-3)*a(n-2) + a(n-4)*a(n-1) + a(n-3)*a(n-1) + a(n-2)*a(n-1).

A121812

a(n) = a(n-4)*a(n-3) + a(n-4)*a(n-2) + a(n-3)*a(n-2) + a(n-4)*a(n-1) + a(n-3)*a(n-1) + a(n-2)*a(n-1).

Terms

    a(0) =0a(1) =1a(2) =1a(3) =1a(4) =3a(5) =12a(6) =67a(7) =1123a(8) =93127a(9) =112028175

External references