Primes formed from the concatenation of n and previousprime(n).

Terms

a(0) =43a(1) =53a(2) =97a(3) =107a(4) =1613a(5) =2423a(6) =3331a(7) =3631a(8) =4241a(9) =4643a(10) =5147a(11) =5347a(12) =5653a(13) =5953a(14) =6361a(15) =6661a(16) =6761a(17) =6967a(18) =7573a(19) =7673a(20) =7873a(21) =8179a(22) =8783a(23) =9689a(24) =102101a(25) =106103a(26) =108107a(27) =111109a(28) =114113a(29) =116113