Numbers k such that k prefixed by '6' and followed by '3' is prime.

Terms

a(0) =1a(1) =4a(2) =5a(3) =7a(4) =8a(5) =11a(6) =13a(7) =14a(8) =16a(9) =17a(10) =20a(11) =26a(12) =32a(13) =34a(14) =35a(15) =37a(16) =47a(17) =55a(18) =56a(19) =65a(20) =67a(21) =70a(22) =73a(23) =76a(24) =79a(25) =80a(26) =82a(27) =83a(28) =86a(29) =88