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Search: id:A072567
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| A072567 |
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Size of maximal set of points in an n X n (side length) grid such that no 4-set of it forms a rectangle with horizontal/vertical sides. |
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+0
1
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| 1, 3, 6, 9, 12, 16, 21, 24, 29, 34, 39, 45, 52
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Finding a(7) is presented as a puzzle in Mathematical Gems III by Ross Honsberger on page 4. - Tanya Khovanova (tanyakh(AT)yahoo.com), Oct 12 2007
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EXAMPLE
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Examples for n=1 and n=2:
*-*....*-*-O
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*-O....*-O-*
.......|.|.|
.......O-*-*
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CROSSREFS
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Sequence in context: A084515 A084525 A130248 this_sequence A061796 A113241 A127621
Adjacent sequences: A072564 A072565 A072566 this_sequence A072568 A072569 A072570
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KEYWORD
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nonn,nice
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AUTHOR
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Xuli Le (leshlie(AT)eyou.com), Jun 21 2002
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EXTENSIONS
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a(1) = 1 from Don Reble, Oct 13 2007
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