A Lyndon word is an aperiodic notation for representing a Necklace.
See also de Bruijn Sequence, Necklace
References
Ruskey, F. ``Information on Necklaces, Lyndon Words, de Bruijn Sequences.''
http://sue.csc.uvic.ca/~cos/inf/neck/NecklaceInfo.html.
Sloane, N. J. A. Sequence
A001037/M0116
in ``An On-Line Version of the Encyclopedia of Integer Sequences.''
http://www.research.att.com/~njas/sequences/eisonline.html and Sloane, N. J. A. and Plouffe, S.
The Encyclopedia of Integer Sequences. San Diego: Academic Press, 1995.