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A277433
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Martin Gardner's minimal no-3-in-a-line problem, all slopes version.
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3
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OFFSET
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1,2
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COMMENTS
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a(n) is the minimal number of counters that can be placed on an n X n grid, no three in a straight line, such that adding one more counter on any vacant grid point will produce three in a line. Lines can have any slope.
The "queens" version of this problem, where lines are restricted to vertical, horizontal and diagonal, is A219760.
a(11) <= 10, a(12) <= 10.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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