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

Terms

a(0) =2a(1) =2a(2) =5a(3) =8a(4) =14a(5) =23a(6) =38a(7) =62a(8) =101a(9) =164a(10) =266a(11) =431a(12) =698a(13) =1130a(14) =1829a(15) =2960a(16) =4790a(17) =7751a(18) =12542a(19) =20294a(20) =32837a(21) =53132a(22) =85970a(23) =139103a(24) =225074a(25) =364178a(26) =589253a(27) =953432a(28) =1542686a(29) =2496119