This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A145547 #8 Oct 05 2017 02:53:39 %S A145547 1,1,2,4,9,20,48,115,286,719,1841,4762,12470,32918,87628,234795, %T A145547 633000,1715435,4671098,12772707,35059815,96567161,266818396,739344427 %N A145547 Number of distinct values taken by 7^7^...^7 (with n 7's and parentheses inserted in all possible ways). %H A145547 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 A145547 <a href="/index/Par#parens">Index entries for sequences related to parenthesizing</a> %Y A145547 Cf. A002845, A003018, A003019, A145545, A145546, A145548, A145549, A145550, A000081. %K A145547 more,nonn %O A145547 1,3 %A A145547 _Jon E. Schoenfield_, Oct 13 2008