Numbers whose concatenation with the next prime yields a prime.

Terms

a(0) =0a(1) =2a(2) =6a(3) =8a(4) =9a(5) =12a(6) =27a(7) =31a(8) =36a(9) =42a(10) =44a(11) =45a(12) =51a(13) =56a(14) =63a(15) =68a(16) =69a(17) =78a(18) =83a(19) =86a(20) =93a(21) =94a(22) =96a(23) =98a(24) =102a(25) =104a(26) =105a(27) =108a(28) =115a(29) =117