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 A102340 Numbers k such that k3333 is prime. 1

%I

%S 2,10,14,31,32,34,35,49,52,73,74,79,80,92,95,97,113,116,118,125,127,

%T 128,134,136,139,142,148,149,155,160,169,172,178,185,196,205,211,217,

%U 224,227,238,245,251,260,262,263,265,272,281,283,284,287,296,298,304,305,311,322,323,325,326,335,343

%N Numbers k such that k3333 is prime.

%H Harvey P. Dale, <a href="/A102340/b102340.txt">Table of n, a(n) for n = 1..1000</a>

%e k=2 is in the sequence because k3333 = 23333 is prime.

%e k=73 is in the sequence because k3333 = 733333 is prime.

%e k=125 is in the sequence because k3333 = 1253333 is prime.

%t Select[Range[500],PrimeQ[FromDigits[Join[IntegerDigits[#],{3,3,3,3}]]]&] (* _Harvey P. Dale_, Jun 17 2014 *)

%o (MAGMA) [ n: n in [1..700] | IsPrime(Seqint([3,3,3,3] cat Intseq(n))) ]; // _Vincenzo Librandi_, Feb 04 2011

%Y Cf. A101472.

%K nonn,base

%O 1,1

%A _Parthasarathy Nambi_, Feb 20 2005

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Last modified June 20 18:42 EDT 2021. Contains 345199 sequences. (Running on oeis4.)