%I #3 Jun 22 2013 11:57:58
%S 23,29,53,101,113,239,281,311,347,353,389,401,431,617,641,647,743,797,
%T 821,827,863,911,941,1049,1283,1319,1373,1439,1481,1487,1493,1511,
%U 1583,1613,1667,1709,1721,1733,1823,1949
%N Prime numbers p such that the concatenation p//1331 is a prime number.
%C Necessarily (as sod(1331) = 3 * 2 + 2): p = 6 * k - 1
%C See comments and references for A174213
%e 231331 = prime(20545) => p(1) = 23 = prime(9)
%e 291331 = prime(25334) => p(2) = 29 = prime(10)
%t Select[Prime[Range[300]],PrimeQ[1331+10000#]&] (* _Harvey P. Dale_, Jun 22 2013 *)
%Y A168327, A168417, A173836, A174213
%K base,nonn
%O 1,1
%A Eva-Maria Zschorn (e-m.zschorn(AT)zaschendorf.km3.de), Mar 14 2010
|