%I A066263
%S A066263 5,6,7,9,10,11,12,13,17,19,20,23,28,31,32,40,43,61,64,79,92,101,104,
%T A066263 127,128,148,167,191,199,313,347,356,596,692,701,1004,1228,1268
%N A066263 2^n+1 has just two distinct prime factors.
%H A066263 Samuel S. Wagstaff, <a href="http://www.cerias.purdue.edu/homes/ssw/cun/
               index.html">The Cunningham Project</a>
%t A066263 f[n_] := First[ Transpose[ FactorInteger[2^n + 1, FactorComplete -> True]]]; 
               Select[ Range[100], Length[f[ # ]] == 2 & ]
%Y A066263 Cf. A073936.
%Y A066263 Sequence in context: A047575 A014097 A081407 this_sequence A089192 A132829 
               A096820
%Y A066263 Adjacent sequences: A066260 A066261 A066262 this_sequence A066264 A066265 
               A066266
%K A066263 nonn
%O A066263 1,1
%A A066263 Benoit Cloitre (benoit7848c(AT)orange.fr), Dec 31 2001
%E A066263 Edited by Robert G. Wilson v (rgwv(AT)rgwv.com), Jan 03 2002