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

A121883

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

Terms

    a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =7a(6) =23a(7) =187a(8) =1049a(9) =11889a(10) =241169a(11) =3461609a(12) =133910987a(13) =6440667383a(14) =259246821927

External references