a(n) = a(n-1) + a(n-2) + 1, with a(0)=3, a(1)=10.

Terms

a(0) =3a(1) =10a(2) =14a(3) =25a(4) =40a(5) =66a(6) =107a(7) =174a(8) =282a(9) =457a(10) =740a(11) =1198a(12) =1939a(13) =3138a(14) =5078a(15) =8217a(16) =13296a(17) =21514a(18) =34811a(19) =56326a(20) =91138a(21) =147465a(22) =238604a(23) =386070a(24) =624675a(25) =1010746a(26) =1635422a(27) =2646169a(28) =4281592a(29) =6927762