Primes which when concatenated with next 3 primes are also prime.

Terms

a(0) =2a(1) =67a(2) =83a(3) =139a(4) =149a(5) =383a(6) =503a(7) =557a(8) =577a(9) =587a(10) =601a(11) =613a(12) =727a(13) =937a(14) =1181a(15) =1259a(16) =1451a(17) =1453a(18) =1489a(19) =1531a(20) =1621a(21) =1657a(22) =1831a(23) =1879a(24) =1907a(25) =2269a(26) =2441a(27) =2531a(28) =2897a(29) =3191