Regular primes.

Terms

a(0) =3a(1) =5a(2) =7a(3) =11a(4) =13a(5) =17a(6) =19a(7) =23a(8) =29a(9) =31a(10) =41a(11) =43a(12) =47a(13) =53a(14) =61a(15) =71a(16) =73a(17) =79a(18) =83a(19) =89a(20) =97a(21) =107a(22) =109a(23) =113a(24) =127a(25) =137a(26) =139a(27) =151a(28) =163a(29) =167