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Search: id:A003019
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| A003019 |
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Number of distinct values taken by 4^4^...^4 (with n 4's and parentheses inserted in all possible ways).
(Formerly M1179)
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+0
11
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| 1, 1, 2, 4, 9, 20, 48, 114, 282, 703, 1787, 4583, 11900, 31131, 82117, 217954, 581970, 1561704, 4210263, 11396488, 30963024, 84402984, 230779071
(list; graph; listen)
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OFFSET
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1,3
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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, A145545, A145546, A145547, A145548, A145549, A145550, A000081.
Sequence in context: A036624 A034823 A036625 this_sequence A036626 A036722 A034824
Adjacent sequences: A003016 A003017 A003018 this_sequence A003020 A003021 A003022
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KEYWORD
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nonn,nice,more
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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a(12) - a(23) from Jon Schoenfield (jonscho(AT)hiwaay.net), Oct 11 2008
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