Search: id:A062721
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%I A062721
%S A062721 4,9,15,21,25,33,39,49,55,69,85,91,111,115,129,133,141,159,169,183,201,
%T A062721 213,235,253,259,265,295,309,319,339,355,361,381,391,403,411,445,451,
%U A062721 469,481,489,493,501,505,511,543,559,565,573,579,589,633,649,655,679
%N A062721 Numbers n such that n is a product of two primes and n-2 is prime.
%H A062721 Zak Seidov, <a href="b062721.txt">Table of n, a(n) for n=1..10000</a>
               .
%t A062721 Select[ Range[ 2, 1500 ], Plus @@ Last@Transpose@FactorInteger[ # ] == 
               2 && PrimeQ[ # - 2 ] & ]
%o A062721 (PARI) { n=0; for (m=1, 10^9, a=prime(m) + 2; f=factor(a)~; if ((length(f)==1 
               && f[2, 1]==2) || (length(f)==2 && f[2, 1]==1 && f[2, 2]==1), write("b062721.txt", 
               n++, " ", a); if (n==10000, break)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), 
               Aug 09 2009]
%Y A062721 Cf. A006512, A001358, A043326.
%Y A062721 Cf. A063637, A046315, A089268.
%Y A062721 Sequence in context: A122927 A078505 A107986 this_sequence A104243 A099055 
               A162801
%Y A062721 Adjacent sequences: A062718 A062719 A062720 this_sequence A062722 A062723 
               A062724
%K A062721 nonn
%O A062721 1,1
%A A062721 Ahmed Fares (ahmedfares(AT)my-deja.com), Jul 14 2001

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