a(1)= 1; a(2)= 5; thereafter a(n)= a(n-1) + a(n-2) + 5.

Terms

a(0) =1a(1) =5a(2) =11a(3) =21a(4) =37a(5) =63a(6) =105a(7) =173a(8) =283a(9) =461a(10) =749a(11) =1215a(12) =1969a(13) =3189a(14) =5163a(15) =8357a(16) =13525a(17) =21887a(18) =35417a(19) =57309a(20) =92731a(21) =150045a(22) =242781a(23) =392831a(24) =635617a(25) =1028453a(26) =1664075a(27) =2692533a(28) =4356613a(29) =7049151