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The shortest sequence such that every string of length  on the Alphabet
 on the Alphabet  occurs as a contiguous subrange of the 
sequence described by
 occurs as a contiguous subrange of the 
sequence described by  .  Every de Bruijn sequence corresponds to an Eulerian Cycle on a de Bruijn Graph.
Surprisingly, it turns out that the lexicographic sequence of Lyndon Words of lengths
Divisible by
.  Every de Bruijn sequence corresponds to an Eulerian Cycle on a de Bruijn Graph.
Surprisingly, it turns out that the lexicographic sequence of Lyndon Words of lengths
Divisible by  gives the lexicographically smallest de Bruijn sequence (Ruskey).
 gives the lexicographically smallest de Bruijn sequence (Ruskey).
References
Ruskey, F.  ``Information on Necklaces, Lyndon Words, de Bruijn Sequences.''  
http://sue.csc.uvic.ca/~cos/inf/neck/NecklaceInfo.html.