a(n) = 5*a(n-1) - a(n-2), a(0) = 3, a(1) = 25.

Terms

a(0) =3a(1) =25a(2) =122a(3) =585a(4) =2803a(5) =13430a(6) =64347a(7) =308305a(8) =1477178a(9) =7077585a(10) =33910747a(11) =162476150a(12) =778470003a(13) =3729873865a(14) =17870899322a(15) =85624622745a(16) =410252214403