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A057725
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Number of "polyares" of order n (turning over not allowed).
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1
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1, 4, 16, 77, 351, 1747, 8745, 44724, 230765, 1203567, 6323074, 33444084, 177863517, 950557538, 5101540598
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OFFSET
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1,2
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COMMENTS
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An n-are is a shape formed from an n-celled polyomino by removing half of each square cell in such a way that at least half of the original join between cells is retained.
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REFERENCES
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Enumeration attributed by Andrew Clarke to Brendan Owen.
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LINKS
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Eric Weisstein's World of Mathematics, Polyare
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CROSSREFS
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KEYWORD
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nonn,nice,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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