A032625 Primes that are concatenations of n with n + 2.

13, 79, 911, 2729, 3739, 4547, 4951, 5153, 5557, 6163, 6971, 7577, 105107, 109111, 115117, 117119, 121123, 151153, 159161, 181183, 187189, 195197, 201203, 211213, 217219, 225227, 247249, 271273, 277279, 285287, 289291

Offset: 1

Author

Patrick De Geest, May 15 1998

Keywords

• nonn
• base

Comments

Or, primes which are the concatenation of two consecutive odd numbers. - Parthasarathy Nambi, Apr 11 2005

Examples

			The first term is 13 which is a prime and is the concatenation of 1 and 3 - the first two odd numbers.
		

Crossrefs

Cf. A032607, A032617.

Programs

Mathematica

lp = Range[1, 320, 2]; lst = {}; Do[p = FromDigits[ Join[ IntegerDigits[ lp[[n]]], IntegerDigits[ lp[[n + 1]] ]]]; If[ PrimeQ[p], AppendTo[lst, p]], {n, 159}]; lst (* Robert G. Wilson v, Apr 12 2005 *)

Extensions

Edited by N. J. A. Sloane, May 21 2008 at the suggestion of R. J. Mathar