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A003008
Number of n-level ladder expressions with A030798.
(Formerly M1147)
1
1, 1, 2, 4, 8, 17, 39, 90, 213
OFFSET
1,3
REFERENCES
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis, Amer. Math. Monthly 80 (8) (1973), 868-876.
R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis. (annotated cached copy)
CROSSREFS
Cf. A003007.
Sequence in context: A036375 A036376 A000598 * A185352 A371726 A054199
KEYWORD
nonn,more
STATUS
approved