a(n) = 5*a(n-1) - 3*a(n-2).

Terms

a(0) =1a(1) =5a(2) =22a(3) =95a(4) =409a(5) =1760a(6) =7573a(7) =32585a(8) =140206a(9) =603275a(10) =2595757a(11) =11168960a(12) =48057529a(13) =206780765a(14) =889731238a(15) =3828313895a(16) =16472375761a(17) =70876937120a(18) =304967558317