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A309506
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Number of cyclic permutations of length n avoiding the pattern 231 (equivalently, 312).
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3
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1, 1, 1, 2, 5, 12, 30, 86, 253, 748, 2274, 7152
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OFFSET
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1,4
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LINKS
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EXAMPLE
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For n=4, there are two such permutations, 4123 and 4312.
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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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