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Number of 7/3+-power-free words over the alphabet {0,1}.
3

%I #17 Apr 27 2015 17:56:52

%S 1,2,4,6,10,14,20,30,38,50,64,86,108,136,178,222,276,330,408,500,618,

%T 774,962,1178,1432,1754,2160,2660,3292

%N Number of 7/3+-power-free words over the alphabet {0,1}.

%H J. Karhumäki and J. Shallit, <a href="http://arXiv.org/abs/math.CO/0304095">Polynomial vs Exponential Growth in Repetition-Free Binary Words</a>

%H A. M. Shur, <a href="http://dx.doi.org/10.1016/j.cosrev.2012.09.001">Growth properties of power-free languages</a>, Computer Science Review, Vol. 6 (2012), 187-208.

%H A. M. Shur, <a href="http://arxiv.org/abs/1009.4415">Numerical values of the growth rates of power-free languages</a>, arXiv:1009.4415 [cs.FL], 2010.

%F Let L = lim a(n)^(1/n); then L exists since a(n) is submultiplicative. 1.2206318 < L < 1.22064482 (Shur 2012); the gap between the bounds can be made less than any given constant. Empirically, the upper bound is precise: L=1.2206448... . - _Arseny Shur_, Apr 26 2015

%Y Cf. A038952, A028445, A007777, A082379.

%K nonn

%O 0,2

%A _Ralf Stephan_, Apr 10 2003

%E Changed name by _Jeffrey Shallit_, Sep 26 2014