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A085577
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Size of maximal subset of the n^2 nodes in an n X n grid such that there at least 3 edges between any pair of nodes.
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1
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1, 1, 2, 4, 6, 8, 10, 13, 17, 20, 25, 29, 34
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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COMMENTS
| The 1-neighborhoods of the nodes must be disjoint: i.e. this is a 1-error correcting code.
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FORMULA
| a(n) approaches n^2/5 as n -> infinity.
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EXAMPLE
| For example, a(3) = 2 (*'s indicate the chosen nodes):
o--o--*
|..|..|
o--o--o
|..|..|
*--o--o
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CROSSREFS
| Main diagonal of A085576.
Sequence in context: A186347 A056827 A024172 * A121832 A006586 A022292
Adjacent sequences: A085574 A085575 A085576 * A085578 A085579 A085580
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KEYWORD
| nonn,more,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), Jul 08 2003
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