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Search: id:A145549
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| A145549 |
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Number of distinct values taken by 9^9^...^9 (with n 9's and parentheses inserted in all possible ways). |
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+0
9
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| 1, 1, 2, 4, 9, 20, 48, 115, 286, 719, 1842, 4766, 12485, 32969, 87795, 235326, 634664, 1720573, 4686829, 12820504, 35204254, 97001655, 268120807, 743236814, 2065709551, 5755253457
(list; graph; listen)
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OFFSET
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1,3
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REFERENCES
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R. K. Guy and J. L. Selfridge, The nesting and roosting habits of the laddered parenthesis. Amer. Math. Monthly 80 (1973), 868-876.
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LINKS
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Index entries for sequences related to parenthesizing
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CROSSREFS
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Cf. A002845, A003018, A003019, A145545, A145546, A145547, A145548, A145550, A000081.
Sequence in context: A145547 A123467 A145548 this_sequence A145550 A000081 A124497
Adjacent sequences: A145546 A145547 A145548 this_sequence A145550 A145551 A145552
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KEYWORD
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more,nonn
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AUTHOR
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Jon E. Schoenfield (jonscho(AT)hiwaay.net), Oct 13 2008
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