a(n) = prime(4n-1).

Terms

a(0) =5a(1) =17a(2) =31a(3) =47a(4) =67a(5) =83a(6) =103a(7) =127a(8) =149a(9) =167a(10) =191a(11) =211a(12) =233a(13) =257a(14) =277a(15) =307a(16) =331a(17) =353a(18) =379a(19) =401a(20) =431a(21) =449a(22) =467a(23) =499a(24) =523a(25) =563a(26) =587a(27) =607a(28) =631a(29) =653