Primes p such that x^3 = 21 has no solution mod p.

Terms

a(0) =19a(1) =31a(2) =37a(3) =61a(4) =67a(5) =97a(6) =103a(7) =109a(8) =127a(9) =139a(10) =151a(11) =157a(12) =181a(13) =193a(14) =199a(15) =211a(16) =223a(17) =271a(18) =307a(19) =313a(20) =331a(21) =337a(22) =373a(23) =379a(24) =397a(25) =409a(26) =421a(27) =463a(28) =487a(29) =499