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A074027
Number of binary Lyndon words of length n with trace 0 and subtrace 0 over Z_2.
7
1, 0, 0, 0, 1, 2, 5, 8, 15, 24, 45, 80, 155, 288, 550, 1024, 1935, 3626, 6885, 13056, 24940, 47616, 91225, 174760, 335626, 645120, 1242600, 2396160, 4627915, 8947294, 17318945, 33554432, 65076240, 126320640, 245424829, 477211280, 928638035, 1808400384, 3524082400
OFFSET
1,6
COMMENTS
Same as the number of binary Lyndon words of length n with trace 0 and subtrace 0 over GF(2).
FORMULA
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.
EXAMPLE
a(6;0,0)=2 since the two binary Lyndon words of trace 0, subtrace 0 and length 6 are { 001111, 010111 }.
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Frank Ruskey and Nate Kube, Aug 21 2002
EXTENSIONS
Terms a(33) onward from Max Alekseyev, Apr 09 2013
STATUS
approved