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A113900
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Number of partitions of 2n X 2n checkerboard into two congruent edgewise-connected sets, counting partitions equal under rotation or reflection only once.
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9
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OFFSET
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1,2
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REFERENCES
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Howard Eves, A Survey of Geometry, 1963, p265.
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LINKS
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EXAMPLE
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All partitions are radially symmetric, hence can be identified by half the cut. The solution for 4 X 4 follows, with coordinates of starting point and direction of each subsequent incremental cut (North is positive Y).
(1,0)NNNES (1,0)NNE (1,0)NEN (1,0)NEENW (2,0)NN (2,0)NENW total = 6
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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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Joseph Sardinha (jsardi3(AT)juno.com), Jan 29 2006
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EXTENSIONS
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New value of a(5) confirmed by and additional values a(6) and a(7) from Andrew Howroyd, Apr 13 2016
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STATUS
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approved
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