a(n) = 5*a(n-3) - a(n-6) with terms 1..6 as 0, 1, 2, 5, 7, 9.

Terms

a(0) =0a(1) =1a(2) =2a(3) =5a(4) =7a(5) =9a(6) =25a(7) =34a(8) =43a(9) =120a(10) =163a(11) =206a(12) =575a(13) =781a(14) =987a(15) =2755a(16) =3742a(17) =4729a(18) =13200a(19) =17929a(20) =22658a(21) =63245a(22) =85903a(23) =108561a(24) =303025a(25) =411586a(26) =520147a(27) =1451880a(28) =1972027a(29) =2492174