a(n) = Lucas(n) + 3.

Terms

a(0) =4a(1) =6a(2) =7a(3) =10a(4) =14a(5) =21a(6) =32a(7) =50a(8) =79a(9) =126a(10) =202a(11) =325a(12) =524a(13) =846a(14) =1367a(15) =2210a(16) =3574a(17) =5781a(18) =9352a(19) =15130a(20) =24479a(21) =39606a(22) =64082a(23) =103685a(24) =167764a(25) =271446a(26) =439207a(27) =710650a(28) =1149854a(29) =1860501