Primes which are the concatenation of two primes in exactly four ways.

Terms

a(0) =233347a(1) =233911a(2) =239929a(3) =337397a(4) =373613a(5) =379397a(6) =733331a(7) =796337a(8) =1321997a(9) =1933331a(10) =2333347a(11) =2333533a(12) =2339929a(13) =2392333a(14) =2393257a(15) =2393761a(16) =2939971a(17) =3136373a(18) =3165713a(19) =3217337a(20) =3319733a(21) =3499277a(22) =3539311a(23) =3727397a(24) =3733967a(25) =3739103a(26) =3739199a(27) =3739397a(28) =3739433