A145548 Number of distinct values taken by 8^8^...^8 (with n 8's and parentheses inserted in all possible ways).

1, 1, 2, 4, 9, 20, 48, 115, 286, 719, 1842, 4765, 12482, 32957, 87756, 235198, 634261, 1719312, 4682952, 12808650, 35168306, 96893138, 267794711, 742260014, 2062792103

Offset

1,3

Links

Table of n, a(n) for n=1..25.

R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis, Amer. Math. Monthly 80 (8) (1973), 868-876.

Index entries for sequences related to parenthesizing

Crossrefs

Cf. A002845, A003018, A003019, A145545, A145546, A145547, A145549, A145550, A000081.

Sequence in context: A318856 A255640 A216403 * A292555 A318804 A318857

Adjacent sequences: A145545 A145546 A145547 * A145549 A145550 A145551

Keyword

more,nonn

Author

Jon E. Schoenfield, Oct 13 2008

Status

approved