Primes with primitive root 21.

Terms

a(0) =2a(1) =19a(2) =23a(3) =29a(4) =31a(5) =53a(6) =71a(7) =97a(8) =103a(9) =107a(10) =113a(11) =137a(12) =139a(13) =149a(14) =157a(15) =179a(16) =181a(17) =191a(18) =197a(19) =223a(20) =233a(21) =239a(22) =263a(23) =271a(24) =281a(25) =307a(26) =313a(27) =317a(28) =347a(29) =359