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Search: id:A145547
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| A145547 |
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Number of distinct values taken by 7^7^...^7 (with n 7's and parentheses inserted in all possible ways). |
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9
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| 1, 1, 2, 4, 9, 20, 48, 115, 286, 719, 1841, 4762, 12470, 32918, 87628, 234795, 633000, 1715435, 4671098, 12772707, 35059815, 96567161, 266818396, 739344427
(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, A145548, A145549, A145550, A000081.
Sequence in context: A034825 A145546 A034826 this_sequence A123467 A145548 A145549
Adjacent sequences: A145544 A145545 A145546 this_sequence A145548 A145549 A145550
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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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