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A234352
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Number of non-equivalent (mod D_3) ways to arrange 4 indistinguishable points on a triangular grid of side n so that no three points are collinear.
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4
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2, 24, 153, 713, 2557, 7661, 20055, 47153, 101821, 205322, 390580, 707708, 1229969, 2060777, 3344487
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OFFSET
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3,1
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COMMENTS
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Without the restriction "non-equivalent (mod D_3)" the numbers are given by A194132.
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LINKS
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EXAMPLE
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There are a(3) = 2 non-equivalent ways to arrange 4 indistinguishable points (x) on a triangular grid of side 3:
x .
x x x x
. x . x . x
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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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EXTENSIONS
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STATUS
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approved
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