Primes that remain prime through 2 iterations of function f(x) = 9x + 4.

Terms

a(0) =3a(1) =7a(2) =31a(3) =37a(4) =41a(5) =71a(6) =73a(7) =83a(8) =107a(9) =191a(10) =283a(11) =307a(12) =317a(13) =337a(14) =373a(15) =421a(16) =631a(17) =743a(18) =773a(19) =821a(20) =857a(21) =883a(22) =967a(23) =1283a(24) =1297a(25) =1361a(26) =1451a(27) =1567a(28) =1571a(29) =1637