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Composite numbers such that some permutation of digits is a prime.
4

%I #11 Nov 21 2013 12:45:55

%S 14,16,20,30,32,34,35,38,50,70,74,76,91,92,95,98,104,106,110,112,115,

%T 118,119,121,124,125,128,130,133,134,136,140,142,143,145,146,152,154,

%U 160,164,166,169,170,172,175,176,182,188,190,194,196,200,203,209,214,215,217,218,230,232,235,236,238,253,272,275,278,287,289,290,292,296,298,299,300

%N Composite numbers such that some permutation of digits is a prime.

%C Conjecture: a(n) ~ 3n/2. - _Charles R Greathouse IV_, Sep 19 2012

%H F. Smarandache, <a href="http://www.gallup.unm.edu/~smarandache/OPNS.pdf">Only Problems, Not Solutions!</a>

%t With[{no=300},Select[Complement[Range[no],Prime[Range[PrimePi[no]]]],MemberQ[PrimeQ[FromDigits/@Permutations[IntegerDigits[#]]],True]&]] (* _Harvey P. Dale_, Feb 06 2011 *)

%K nonn,base,easy

%O 1,1

%A R. Muller

%E More terms from Joe DeMaio (jdemaio(AT)kennesaw.edu)