A337613 Lexicographically earliest sequence of distinct positive integers such that the concatenation of any two successive digits forms a prime.

1, 3, 7, 9, 71, 11, 13, 17, 19, 73, 79, 711, 31, 37, 97, 111, 113, 117, 119, 713, 131, 137, 171, 173, 179, 717, 197, 311, 313, 719, 731, 317, 319, 737, 371, 373, 797, 379, 7111, 971, 973, 1111, 979, 7113, 1113, 1117, 1119, 7117, 1131, 1137, 1171, 1173, 1179, 7119, 7131, 1197, 1311, 1313, 1317, 1319, 7137

Offset: 1

Author

Eric Angelini and Jean-Marc Falcoz, Sep 05 2020

Keywords

• base
• nonn

Comments

Only the digits 1, 3, 7 and 9 are in the sequence as a term ending in 0, 2, 4, 5, 6 or 8 would not be prime.

Examples

			The first terms 1, 3, 7, 9, 71, 11, 13, 17,... form (when 2 successive digits are concatenated) the prime numbers 13, 37, 79, 97, 11, 11, 31, 17,...
		

Crossrefs

Cf. A337614 (same idea, 3 successive digits).