Search: id:A145549 Results 1-1 of 1 results found. %I A145549 %S A145549 1,1,2,4,9,20,48,115,286,719,1842,4766,12485,32969,87795,235326,634664, %T A145549 1720573,4686829,12820504,35204254,97001655,268120807,743236814, %U A145549 2065709551,5755253457 %N A145549 Number of distinct values taken by 9^9^...^9 (with n 9's and parentheses inserted in all possible ways). %D A145549 R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis. Amer. Math. Monthly 80 (1973), 868-876. %H A145549 Index entries for sequences related to parenthesizing %Y A145549 Cf. A002845, A003018, A003019, A145545, A145546, A145547, A145548, A145550, A000081. %Y A145549 Sequence in context: A145547 A123467 A145548 this_sequence A145550 A000081 A124497 %Y A145549 Adjacent sequences: A145546 A145547 A145548 this_sequence A145550 A145551 A145552 %K A145549 more,nonn %O A145549 1,3 %A A145549 Jon E. Schoenfield (jonscho(AT)hiwaay.net), Oct 13 2008 Search completed in 0.001 seconds