Numbers k such that k prefixed by '1' and followed by '7' is prime.

Terms

a(0) =0a(1) =2a(2) =3a(3) =5a(4) =6a(5) =9a(6) =11a(7) =18a(8) =21a(9) =23a(10) =27a(11) =29a(12) =30a(13) =32a(14) =36a(15) =42a(16) =44a(17) =48a(18) =56a(19) =59a(20) =60a(21) =62a(22) =63a(23) =65a(24) =66a(25) =69a(26) =74a(27) =77a(28) =78a(29) =84