Primes formed from the concatenation of k, k+1 and k for some k.

Terms

a(0) =787a(1) =9109a(2) =111211a(3) =131413a(4) =333433a(5) =373837a(6) =394039a(7) =414241a(8) =474847a(9) =575857a(10) =596059a(11) =616261a(12) =697069a(13) =717271a(14) =777877a(15) =798079a(16) =818281a(17) =838483a(18) =101102101a(19) =103104103a(20) =129130129a(21) =149150149a(22) =181182181a(23) =187188187a(24) =189190189a(25) =191192191a(26) =193194193a(27) =207208207a(28) =217218217