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A174260 Prime numbers p such that the concatenation p//1331 is a prime number. 5
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 (list; graph; refs; listen; history; text; internal format)
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: A108249 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

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Last modified May 22 00:25 EDT 2019. Contains 323472 sequences. (Running on oeis4.)