%I A143584
%S A143584 11,23,25,28,29,35,36,37,39
%N A143584 a(n) is the multiplicative order of 2 modulo some overpseudoprime to 
               base 2.
%C A143584 A064078(a(n)) is composite number. The sequence have a positive density 
               since
%C A143584 contains, in particular, numbers of the form 8n+20 for n>=1 (C.Pomerance, 
               private correspondence). Since, e. g., 38 is not in the sequence, 
               then there is not an overpseudoprime m such that ord_m(2)=38.
%Y A143584 Cf. A141232 A002326 A064078 A122929.
%Y A143584 Sequence in context: A032663 A119815 A046624 this_sequence A061752 A122259 
               A157173
%Y A143584 Adjacent sequences: A143581 A143582 A143583 this_sequence A143585 A143586 
               A143587
%K A143584 nonn
%O A143584 1,1
%A A143584 Vladimir Shevelev (shevelev(AT)bgu.ac.il), Aug 25 2008