Numbers k such that k concatenated with k+6 is a prime.

Terms

a(0) =1a(1) =11a(2) =13a(3) =17a(4) =25a(5) =31a(6) =35a(7) =43a(8) =65a(9) =71a(10) =83a(11) =95a(12) =97a(13) =101a(14) =125a(15) =127a(16) =137a(17) =151a(18) =155a(19) =157a(20) =161a(21) =163a(22) =167a(23) =187a(24) =197a(25) =203a(26) =205a(27) =211a(28) =217a(29) =221