A003007 Number of n-level ladder expressions with A002193. (Formerly M1145)

1, 1, 2, 4, 8, 17, 38, 89, 208

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. A003008.

Sequence in context: A006461 A257300 A229202 * A086615 A357903 A081124

Adjacent sequences: A003004 A003005 A003006 * A003008 A003009 A003010

Keyword

nonn,more

Author

N. J. A. Sloane

Status

approved