a(0)=1, a(1)=4, a(n) = a(n-1) + a(n-2) - 1.

Terms

a(0) =1a(1) =4a(2) =4a(3) =7a(4) =10a(5) =16a(6) =25a(7) =40a(8) =64a(9) =103a(10) =166a(11) =268a(12) =433a(13) =700a(14) =1132a(15) =1831a(16) =2962a(17) =4792a(18) =7753a(19) =12544a(20) =20296a(21) =32839a(22) =53134a(23) =85972a(24) =139105a(25) =225076a(26) =364180a(27) =589255a(28) =953434a(29) =1542688