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

1,1

Comments

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

See comments and references for A174213

Links

Table of n, a(n) for n=1..40.

Example

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

Mathematica

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

Crossrefs

A168327, A168417, A173836, A174213

Sequence in context: A338324 A232725 A045120 * A097436 A063980 A046124

Adjacent sequences: A174257 A174258 A174259 * A174261 A174262 A174263

Keyword

base,nonn

Author

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

Status

approved