Séminaire Lotharingien de Combinatoire, B23e (1990).
[Formerly: Publ. I.R.M.A. Strasbourg, 1992, 460/S-23, p.
77-83.]
Daniéle Gardy and Dominique Gouyou-Beauchamps
Enumeration of Some Davenport-Schinzel Sequences
Abstract.
Davenport-Schinzel sequences of order s are words with no
subsequence ababa... of length s+2. We give enumeration results
for the case s=2. in particular, we related some of these
sequences to Catalan and Schröder numbers.
The paper has been finally published under the title
"Enumerating Davenport-Schinzel sequences" in
RAIRO Inform. Théor. Appl. 26 (1992), 387-402.