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Primes that are a concatenation of 2, 3 and a prime.
6

%I #9 Aug 11 2014 22:45:25

%S 233,2311,2341,2347,2371,2383,2389,23131,23167,23173,23197,23227,

%T 23251,23269,23293,23311,23431,23509,23557,23563,23593,23599,23677,

%U 23719,23743,23761,23773,23827,23857,23887,23911,23929,23971,23977,231019

%N Primes that are a concatenation of 2, 3 and a prime.

%H Harvey P. Dale, <a href="/A101218/b101218.txt">Table of n, a(n) for n = 1..1000</a>

%H Peter Alfeld <a href="http://www.math.utah.edu/~alfeld/math/p10000.html">The 10,000 smallest prime numbers</a>.

%e 233 is a prime concatenated from the primes 2,3 and 3

%e 2311 is a prime concatenated from the primes 2,3 and 11

%t Select[23*10^IntegerLength[#]+#&/@Prime[Range[200]],PrimeQ] (* _Harvey P. Dale_, Jun 09 2013 *)

%Y Cf. A100607, A101219, A101249, A101250, A101251, A101252.

%K nonn,base,easy

%O 1,1

%A _Parthasarathy Nambi_, Dec 14 2004

%E Extended by _Ray Chandler_, Dec 22, 2004