%I A124720
%S A124720 2,5,16,38,96,220,512,1144,2560,5616,12288,26592,57344,122816,262144,
%T A124720 556928,1179648,2490112,5242880,11009536,23068672,48233472,100663296,
%U A124720 209713152,436207616,905965568,1879048192,3892305920,8053063680
%N A124720 Number of ternary Lyndon words with exactly two 1's.
%C A124720 If the offsets are modified, A124720 to A124723 are the 2nd to 5th Witt 
               transform of A000079 [Moree]. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Nov 08 2008]
%H A124720 Pieter Moree, <a href="http://dx.doi.org/10.1016/j.disc.2005.03.004">
               The formal series Witt transform</a>, Discr. Math. no. 295 vol. 1-3 
               (2005) 143-160. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), 
               Nov 08 2008]
%F A124720 G.f.: x^3*(2-3 x)/((1-2 x^2)(1- 2x)^2) = (x^2/(1-2x)^2 - x^2/(1-2*x^2))/
               2
%e A124720 a(4) = 5 because 1122, 1123, 1132, 1213, 1133 are all Lyndon words on 
               3 letters with 2 ones.
%Y A124720 Cf. A051168, A027376, A124721, A124722, A124723.
%Y A124720 Sequence in context: A053683 A082085 A054971 this_sequence A076958 A163825 
               A102866
%Y A124720 Adjacent sequences: A124717 A124718 A124719 this_sequence A124721 A124722 
               A124723
%K A124720 nonn
%O A124720 3,1
%A A124720 Mike Zabrocki (zabrocki(AT)mathstat.yorku.ca), Nov 05 2006