0,7

a(n-1)=number of aperiodic necklaces (Lyndon words) with 5 black beads and n-5 white beads.

D. J. Broadhurst, On the enumeration of irreducible k-fold Euler sums and their roles in knot theory and field theory

Index entries for sequences related to Lyndon words

G.f.: x^5(1+x^3)/((1-x)^3(1-x^2)(1-x^5)).

seq(floor(binomial(n, 4)/5), n=0.. 40); # [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jan 12 2009]

Cf. A000031, A001037, A051168. Same as A051170(n+1).

A column of triangle A011847.

Sequence in context: A004006 A089240 A057524 this_sequence A051170 A008646 A036830

Adjacent sequences: A011792 A011793 A011794 this_sequence A011796 A011797 A011798

nonn,easy

N. J. A. Sloane (njas(AT)research.att.com), David Broadhurst (D.Broadhurst(AT)open.ac.uk)