Lucky numbers that are concatenations of n with n + 2.

Terms

a(0) =13a(1) =79a(2) =1921a(3) =2527a(4) =3133a(5) =4951a(6) =6163a(7) =6567a(8) =7173a(9) =7779a(10) =101103a(11) =103105a(12) =107109a(13) =121123a(14) =125127a(15) =133135a(16) =139141a(17) =149151a(18) =157159a(19) =169171a(20) =173175a(21) =193195a(22) =205207a(23) =221223a(24) =233235a(25) =245247a(26) =295297a(27) =349351a(28) =359361a(29) =371373