a(n) = 5*a(n-1) + 3 with a(0) = 1.

Terms

a(0) =1a(1) =8a(2) =43a(3) =218a(4) =1093a(5) =5468a(6) =27343a(7) =136718a(8) =683593a(9) =3417968a(10) =17089843a(11) =85449218a(12) =427246093a(13) =2136230468a(14) =10681152343a(15) =53405761718a(16) =267028808593