%I #8 Oct 05 2017 02:53:46

%S 1,1,2,4,9,20,48,115,286,719,1842,4765,12482,32957,87756,235198,

%T 634261,1719312,4682952,12808650,35168306,96893138,267794711,

%U 742260014,2062792103

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

%H R. K. Guy and J. L. Selfridge, <a href="http://www.jstor.org/stable/2319392">The nesting and roosting habits of the laddered parenthesis</a>, Amer. Math. Monthly 80 (8) (1973), 868-876.

%H <a href="/index/Par#parens">Index entries for sequences related to parenthesizing</a>

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

%K more,nonn

%O 1,3

%A _Jon E. Schoenfield_, Oct 13 2008