Primes starting and ending with 3.

Terms

a(0) =3a(1) =313a(2) =353a(3) =373a(4) =383a(5) =3023a(6) =3083a(7) =3163a(8) =3203a(9) =3253a(10) =3313a(11) =3323a(12) =3343a(13) =3373a(14) =3413a(15) =3433a(16) =3463a(17) =3533a(18) =3583a(19) =3593a(20) =3613a(21) =3623a(22) =3643a(23) =3673a(24) =3733a(25) =3793a(26) =3803a(27) =3823a(28) =3833a(29) =3853