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Search: id:A107987
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%I A107987
%S A107987 9,15,21,25,33,39,45,49,55,63,69,75,81,85,91,99,105,111,115,129,133,141,
%T A107987 153,159,165,169,175,183,195,201,213,225,231,235,243,253,259,265,273,
%U A107987 279,285,295,309,315,319,333,339,351,355,361,369,375,381,385,391,399
%N A107987 Odd composite numbers of the form p+2 where p is prime.
%o A107987 (PARI) sum2pr(n) = \Composite numbers of form p+2. { c=0; cp=0; forprime(x=2,
               n, cp++; y=x+2; if(isprime(y)==0, c++; print1(y",") ) ); print(); 
               print(c/cp+.) }
%Y A107987 Cf. A067774.
%Y A107987 Sequence in context: A046315 A046372 A025045 this_sequence A031879 A139787 
               A063139
%Y A107987 Adjacent sequences: A107984 A107985 A107986 this_sequence A107988 A107989 
               A107990
%K A107987 easy,nonn
%O A107987 1,1
%A A107987 Cino Hilliard (hillcino368(AT)gmail.com), Jun 13 2005

    
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Last modified November 27 22:38 EST 2009. Contains 167602 sequences.


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