A003008 Number of n-level ladder expressions with A030798. (Formerly M1147)

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

Table of n, a(n) for n=1..9.

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)

Index entries for sequences related to parenthesizing

Crossrefs

Cf. A003007.

Sequence in context: A036375 A036376 A000598 * A185352 A371726 A054199

Adjacent sequences: A003005 A003006 A003007 * A003009 A003010 A003011

Keyword

nonn,more

Author

N. J. A. Sloane

Status

approved