%I A112927
%S A112927 1,3,7,5,31,1,127,17,73,11,23,13,8191,43,151,257,131071,19,524287,41,
%T A112927 337,683,47,241,601,2731,262657,29,233,331,2147483647,65537,599479,
%U A112927 43691,71,37,223,174763,79,61681
%N A112927 a(n) is the least prime such that the multiplicative order of 2 mod a(n) 
               equals n, or a(n)=1 if no such prime exists.
%C A112927 If a(n) differs from 1, then a(n) is the minimal prime divisor of A064078(n);
%C A112927 a(n)=n+1 iff n+1 is prime from A001122; a(n)=2n+1 iff 2n+1 is prime from 
               A115591.
%Y A112927 Cf. A002326 A064078 A001122 A115591.
%Y A112927 Sequence in context: A112071 A046561 A097406 this_sequence A064078 A048857 
               A005420
%Y A112927 Adjacent sequences: A112924 A112925 A112926 this_sequence A112928 A112929 
               A112930
%K A112927 nonn
%O A112927 1,2
%A A112927 Vladimir Shevelev (shevelev(AT)bgu.ac.il), Aug 25 2008