a(n) = floor(5^n/3^n).

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =7a(5) =12a(6) =21a(7) =35a(8) =59a(9) =99a(10) =165a(11) =275a(12) =459a(13) =765a(14) =1276a(15) =2126a(16) =3544a(17) =5907a(18) =9846a(19) =16410a(20) =27351a(21) =45585a(22) =75975a(23) =126625a(24) =211042a(25) =351737a(26) =586229a(27) =977048a(28) =1628414a(29) =2714024