Primes formed from the concatenation of n, n-1 and n for some n > 0.

Terms

a(0) =101a(1) =131213a(2) =171617a(3) =313031a(4) =333233a(5) =434243a(6) =474647a(7) =494849a(8) =636263a(9) =777677a(10) =898889a(11) =939293a(12) =117116117a(13) =119118119a(14) =127126127a(15) =133132133a(16) =151150151a(17) =159158159a(18) =161160161a(19) =163162163a(20) =199198199a(21) =243242243a(22) =269268269a(23) =273272273a(24) =277276277