a(n) = a(n-1) + a(n-2) + 1, with a(0) = 0 and a(1) = 8.

Terms

a(0) =0a(1) =8a(2) =9a(3) =18a(4) =28a(5) =47a(6) =76a(7) =124a(8) =201a(9) =326a(10) =528a(11) =855a(12) =1384a(13) =2240a(14) =3625a(15) =5866a(16) =9492a(17) =15359a(18) =24852a(19) =40212a(20) =65065a(21) =105278a(22) =170344a(23) =275623a(24) =445968a(25) =721592a(26) =1167561a(27) =1889154a(28) =3056716a(29) =4945871