a(n) = prime(3n-1).

Terms

a(0) =3a(1) =11a(2) =19a(3) =31a(4) =43a(5) =59a(6) =71a(7) =83a(8) =101a(9) =109a(10) =131a(11) =149a(12) =163a(13) =179a(14) =193a(15) =211a(16) =229a(17) =241a(18) =263a(19) =277a(20) =293a(21) =313a(22) =337a(23) =353a(24) =373a(25) =389a(26) =409a(27) =431a(28) =443a(29) =461