A111070 Twin prime pairs using digits 1 and 3 only.

11, 13, 311, 313, 131111, 131113, 313331, 313333, 1131131, 1131133, 3331331, 3331333, 3333131, 3333133, 3333311, 3333313, 111113111, 111113113, 113331311, 113331313, 331313111, 331313113, 331331111, 331331113, 333331331, 333331333

Offset

1,1

Comments

Both the members of the twin prime pairs are included.

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(2k) = a(2k-1) + 2.

Mathematica

s = Select[Flatten @ Table[FromDigits /@ Tuples[{1, 3}, k], {k, 1, 9}], And @@ PrimeQ[10 # + {1, 3}] &]; Flatten @ Transpose @ {10 s + 1, 10 s + 3} (* Amiram Eldar, Dec 28 2019 *)

Crossrefs

Cf. A001097, A001359, A006512.

Sequence in context: A093605 A288304 A155967 * A110115 A073765 A360277

Adjacent sequences: A111067 A111068 A111069 * A111071 A111072 A111073

Keyword

base,nonn

Author

Amarnath Murthy, Jan 02 2006

Extensions

Corrected and extended by Farideh Firoozbakht, Jan 05 2006

Status

approved