Primes formed by concatenating a prime with the preceding prime.

Terms

a(0) =53a(1) =5347a(2) =5953a(3) =6761a(4) =137131a(5) =179173a(6) =211199a(7) =223211a(8) =239233a(9) =263257a(10) =359353a(11) =541523a(12) =593587a(13) =613607a(14) =631619a(15) =653647a(16) =659653a(17) =757751a(18) =809797a(19) =977971a(20) =997991a(21) =1009997a(22) =11091103a(23) =11291123a(24) =12371231a(25) =13991381a(26) =15591553a(27) =17831777a(28) =19311913a(29) =19791973