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A192865
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Number of set partitions of {1,...,n} that avoid enhanced 5-crossings (or 5-nestings)
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2
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1, 1, 2, 5, 15, 52, 203, 877, 4140, 21146, 115945, 678012, 4205209, 27531954, 189486817, 1365888674, 10278272450, 80503198320, 654544093035, 5511256984436, 47950929125540
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OFFSET
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0,3
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LINKS
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EXAMPLE
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There are 21147 partitions of 9 elements, but a(9)=21146 because the partition {1,9}{2,8}{3,7}{4, 6}{5} has an enhanced 5-nesting.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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