%I A139690
%S A139690 4,5,7,9,13,15,19,21,25,31,33,39,43,49,55,61,69,73,85,91,103,109,111,
%T A139690 115,129,133,139,141,151,159,169,181,183,193,199,201,213,229,235,241,
%U A139690 253,259,265,271,283,295,309,313,319,339,349,355,361,381,391,403,411
%N A139690 A109611(n) + 2.
%C A139690 Intersection of A052147 and A037143; A006512 is a subsequence;
%C A139690 A010051(a(n)) = A139689(n); A064911(a(n)) = 1 - A139689(n);
%C A139690 A001222(a(n)) = 2 - A139689(n).
%H A139690 R. Zumkeller, <a href="b139690.txt">Table of n, a(n) for n = 1..1000</
               a>
%H A139690 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               ChenPrime.html">Chen Prime</a>
%Y A139690 Sequence in context: A032360 A117150 A052147 this_sequence A035266 A035264 
               A153085
%Y A139690 Adjacent sequences: A139687 A139688 A139689 this_sequence A139691 A139692 
               A139693
%K A139690 nonn
%O A139690 1,1
%A A139690 Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Apr 29 2008