A241903 - OEIS

%I #21 May 16 2016 08:20:59

%S 1,2,4,6,10,16,24,34,48,62,80,100,124,148,178,210,244,282,324,372,426,

%T 488,556,630,712,804,908,1024,1152,1296,1454,1626,1814,2018,2244,2490,

%U 2756,3044,3354,3690,4050,4438,4856,5300,5772,6272,6800,7370,7966,8598,9266,9964,10708,11484,12300,13166

%N Number of binary strings of length n avoiding the pattern x x x^R (where x^R means reverse of x).

%H Giovanni Resta, <a href="/A241903/b241903.txt">Table of n, a(n) for n = 0..300</a>

%H James Currie, Narad Rampersad, <a href="http://arxiv.org/abs/1502.07014">Growth rate of binary words avoiding xxx^R</a>, arXiv preprint arXiv:1502.07014, 2015

%H J. D. Currie and N. Rampersad. Growth rate of binary words avoiding xxxR. Theoret. Comput. Sci. 609 (2016), 456-468.

%H Chen Fei Du, Hamoon Mousavi, Luke Schaeffer, and Jeffrey Shallit, <a href="http://arxiv.org/abs/1406.0670">Decision Algorithms for Fibonacci-Automatic Words, with Applications to Pattern Avoidance</a>, preprint, June 3 2014

%e For n=4 the strings {0000,0001,0111,1000,1110,1111} have instances of x x x^R, so a(4) = 16-6 = 10.

%K nonn

%O 0,2

%A _Jeffrey Shallit_, May 01 2014