%I A002184 M4400 N1855
%S A002184 1,7,31,127,73,23,8191,151,131071,524287,337,47,601,262657,233,
%T A002184 2147483647,599479,71,223,79,13367,431,631,2351,4432676798593,103,6361,
%U A002184 881,32377,179951,2305843009213693951,92737,145295143558111
%N A002184 a(n) = least primitive factor of 2^(2n+1) - 1.
%D A002184 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A002184 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 
               (includes this sequence).
%D A002184 J. Brillhart et al., Factorizations of b^n +- 1. Contemporary Mathematics, 
               Vol. 22, Amer. Math. Soc., Providence, RI, 2nd edition, 1985; and 
               later supplements.
%D A002184 M. Kraitchik, Recherches sur la Th\'{e}orie des Nombres. Gauthiers-Villars, 
               Paris, Vol. 1, 1924, Vol. 2, 1929, see Vol. 2, p. 84.
%H A002184 J. Brillhart et al., <a href="http://www.ams.org/online_bks/conm22/">
               Factorizations of b^n +- 1</a>, Contemporary Mathematics, Vol. 22, 
               Amer. Math. Soc., Providence, RI, 3rd edition, 2002.
%H A002184 S. S. Wagstaff, Jr., <a href="http://www.cerias.purdue.edu/homes/ssw/
               cun/index.html">The Cunningham Project</a>
%Y A002184 Cf. A002588.
%Y A002184 Sequence in context: A147597 A048775 A125193 this_sequence A002588 A036280 
               A153005
%Y A002184 Adjacent sequences: A002181 A002182 A002183 this_sequence A002185 A002186 
               A002187
%K A002184 nonn
%O A002184 0,2
%A A002184 N. J. A. Sloane (njas(AT)research.att.com).
%E A002184 More terms from Don Reble (djr(AT)nk.ca), Nov 14 2006