Twin prime pairs using digits 1 and 3 only.

Terms

a(0) =11a(1) =13a(2) =311a(3) =313a(4) =131111a(5) =131113a(6) =313331a(7) =313333a(8) =1131131a(9) =1131133a(10) =3331331a(11) =3331333a(12) =3333131a(13) =3333133a(14) =3333311a(15) =3333313a(16) =111113111a(17) =111113113a(18) =113331311a(19) =113331313a(20) =331313111a(21) =331313113a(22) =331331111a(23) =331331113a(24) =333331331a(25) =333331333