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Search: id:A085489
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| A085489 |
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a(n) = number of subsets of {1,...,n} containing no solutions to x+y=z with x and y distinct (one version of "sum-free subsets"). |
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+0
7
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| 2, 4, 7, 13, 22, 37, 61, 102, 162, 261, 410, 646, 1001, 1553, 2370, 3645, 5515, 8303, 12470, 18713, 27811, 41244, 60962, 89733, 131870, 192522, 281125, 408680, 593880, 855661, 1238592, 1779614, 2563476, 3660084, 5255913, 7473380, 10696444, 15137517
(list; graph; listen)
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OFFSET
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1,1
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LINKS
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Eric Weisstein's World of Mathematics, Sum-Free Set [Strictly speaking this link is not relevant, since it uses a different definition of "sum-free".]
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FORMULA
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a(n) = 2^n - A088809(n). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Oct 19 2003
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CROSSREFS
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See A007865 for another version.
Sequence in context: A143823 A119983 A151897 this_sequence A101268 A128768 A001036
Adjacent sequences: A085486 A085487 A085488 this_sequence A085490 A085491 A085492
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KEYWORD
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nonn,nice
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AUTHOR
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Eric Weisstein (eric(AT)weisstein.com), Jul 02, 2003
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EXTENSIONS
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More terms from Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Jul 13 2003
Edited by David Wasserman (dwasserm(AT)earthlink.net), Apr 16 2008
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