Smallest prime obtained by sandwiching prime(n) between identical digits, except that a(5) = 0.

Terms

a(0) =727a(1) =131a(2) =151a(3) =373a(4) =0a(5) =331333a(6) =1171a(7) =9199a(8) =1231a(9) =1291a(10) =3313a(11) =3373a(12) =3413a(13) =3433a(14) =1471a(15) =1531a(16) =3593a(17) =3613a(18) =3673a(19) =7717a(20) =3733a(21) =3793a(22) =1831a(23) =1111891111a(24) =11197111a(25) =31013a(26) =31033a(27) =11071a(28) =91099a(29) =11131