A174260 Prime numbers p such that the concatenation p//1331 is a prime number.

23, 29, 53, 101, 113, 239, 281, 311, 347, 353, 389, 401, 431, 617, 641, 647, 743, 797, 821, 827, 863, 911, 941, 1049, 1283, 1319, 1373, 1439, 1481, 1487, 1493, 1511, 1583, 1613, 1667, 1709, 1721, 1733, 1823, 1949

Offset: 1

Author

Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 14 2010

Keywords

• base
• nonn

Comments

Necessarily (as sod(1331) = 3 * 2 + 2): p = 6 * k - 1

See comments and references for A174213

Examples

			231331 = prime(20545) => p(1) = 23 = prime(9)
291331 = prime(25334) => p(2) = 29 = prime(10)
		

Crossrefs

A168327, A168417, A173836, A174213

Programs

Mathematica

Select[Prime[Range[300]],PrimeQ[1331+10000#]&] (* Harvey P. Dale, Jun 22 2013 *)