Fibonacci sequence beginning 3, 9.

Terms

a(0) =3a(1) =9a(2) =12a(3) =21a(4) =33a(5) =54a(6) =87a(7) =141a(8) =228a(9) =369a(10) =597a(11) =966a(12) =1563a(13) =2529a(14) =4092a(15) =6621a(16) =10713a(17) =17334a(18) =28047a(19) =45381a(20) =73428a(21) =118809a(22) =192237a(23) =311046a(24) =503283a(25) =814329a(26) =1317612a(27) =2131941a(28) =3449553a(29) =5581494