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A181148
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Number of distinct oval-partitions of the regular 2n-gon {2n}.
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1
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OFFSET
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1,5
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COMMENTS
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For each n there is a list of floor{n/2} rhombs, a four-sided parallelogram with principal index a number from {1, 2, ..., floor(n/2)}. Such rhombs can tile an (n,k)-oval. An (n,k)-oval is a centro-symmetric polygon with 2k sides and contains k(k-1)/2 rhombs. The regular 2n-gon {2n} with 2n sides is an (n, n)-oval, its rhombs can be partitioned into (n, k)-ovals for various values of k. This partition is called an oval-partition of {2n}. An oval-partition is distinct if every oval in the partition is different. Here, a(n) is the number of distinct oval-partitions of {2n}.
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LINKS
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CROSSREFS
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Sequence A177921 gives the total number of oval-partitions of {2n}, distinct or not.
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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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Term a(8) corrected and sequence explanation improved by John P. McSorley, Feb 26 2011
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STATUS
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approved
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