%I A104239
%S A104239 0,1,2,2,2,3,2,5,3,1,4,3,3,2,3,1,5,5,7,4,5,5,4,5,5,2,4,5,4,6,5,3,7,1,4,
%T A104239 4,3,4,3,6,5,7,5,7,8,4,7,7,1,6
%N A104239 Number of distinct prime factors of 135...(2n-1) (concatenation of n 
               odd numbers).
%C A104239 Interestingly, 135791113151719 is prime.
%H A104239 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               ConsecutiveNumberSequences.html">Consecutive Number sequences</a>
%e A104239 The number of distinct prime factors of 13 is 1 (a prime) - the second 
               term in the sequence.
%e A104239 The number of distinct prime factors of 135 is 2 - the third term in 
               the sequence.
%e A104239 The number of distinct prime factors of 1357 is 2 - the fourth term in 
               the sequence.
%Y A104239 Cf. A001221, A048847.
%Y A104239 Sequence in context: A121611 A046798 A157231 this_sequence A058614 A058726 
               A132321
%Y A104239 Adjacent sequences: A104236 A104237 A104238 this_sequence A104240 A104241 
               A104242
%K A104239 nonn,base
%O A104239 1,3
%A A104239 Parthasarathy Nambi (PachaNambi(AT)yahoo.com), Apr 16 2005
%E A104239 Corrected and extended by Frank Adams-Watters (FrankTAW(AT)Netscape.net), 
               Sep 01 2006
%E A104239 Edited by N. J. A. Sloane (njas(AT)research.att.com), May 21 2008 at 
               the suggestion of R. J. Mathar