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A040018
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(Number of permutations of {1,2,...,n} for which sums of adjacent numbers are all distinct)/2n.
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5
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1, 1, 3, 8, 46, 176, 955, 5446, 36122, 259084, 2043944, 17371318, 159616680, 1566391958
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OFFSET
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3,3
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COMMENTS
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Essentially different ways 1,2,3,...,n can be placed around a circle so that sums of adjacent numbers are distinct.
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LINKS
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CROSSREFS
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KEYWORD
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nonn,hard,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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