login
Number of binary Lyndon words of length n with trace 0 and subtrace 0 over Z_2.
7

%I #17 May 03 2019 07:21:56

%S 1,0,0,0,1,2,5,8,15,24,45,80,155,288,550,1024,1935,3626,6885,13056,

%T 24940,47616,91225,174760,335626,645120,1242600,2396160,4627915,

%U 8947294,17318945,33554432,65076240,126320640,245424829,477211280,928638035,1808400384,3524082400

%N Number of binary Lyndon words of length n with trace 0 and subtrace 0 over Z_2.

%C Same as the number of binary Lyndon words of length n with trace 0 and subtrace 0 over GF(2).

%H Max Alekseyev, <a href="http://home.gwu.edu/~maxal/gpscripts/">PARI/GP scripts for miscellaneous math problems</a>

%H F. Ruskey, <a href="http://combos.org/TSlyndonZ2">Binary Lyndon words with given trace and subtrace</a>

%H F. Ruskey, <a href="http://combos.org/TSlyndonF2">Binary Lyndon words with given trace and subtrace over GF(2)</a>

%F a(2n) = A042979(2n), a(2n+1) = A042980(2n+1). This follows from Cattell et al. (see A042979), Main Theorem on p. 33 and Theorem 4 on p. 44.

%e a(6;0,0)=2 since the two binary Lyndon words of trace 0, subtrace 0 and length 6 are { 001111, 010111 }.

%Y Cf. A074028, A074029, A074030.

%K easy,nonn

%O 1,6

%A _Frank Ruskey_ and Nate Kube, Aug 21 2002

%E Terms a(33) onward from _Max Alekseyev_, Apr 09 2013