A220587 - OEIS

%I #8 Jan 30 2016 18:27:34

%S 2,1,2,1,6,5,18,17,55,55,186,185,630,629,2181,2181,7710,7709,27594,

%T 27593,99857,99857

%N Number of Lyndon words appearing as n-th degree terms in Baker-Campbell-Hausdorff series.

%H Dror Bar-Natan, <a href="http://mathoverflow.net/questions/116137/the-bch-series-in-terms-of-lyndon-words">The BCH series in terms of Lyndon words</a>, MathOverflow.

%H Dror Bar-Natan, <a href="http://drorbn.net/AcademicPensieve/2012-12/nb/BCH-Lyndon_Question.pdf">A BCH-Lyndon Question</a>.

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Baker%E2%80%93Campbell%E2%80%93Hausdorff_formula">Baker-Campbell-Hausdorff formula</a>

%H Wikipedia, <a href="http://en.wikipedia.org/wiki/Lyndon_word">Lyndon word</a>

%Y Cf. A001037.

%K nonn,more

%O 1,1

%A Dror Bar-Natan, communicated by _Max Alekseyev_, Dec 16 2012