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A023995
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Number of sets S = {a_1, a_2, ..., a_k}, with 1 < a_i < a_j <= n such that no a_j divides the product of all the others.
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3
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1, 2, 4, 6, 12, 16, 32, 44, 64, 86, 172, 204, 408, 544, 660, 860, 1720, 2080, 4160, 4800, 5792, 7784, 15568, 17440, 23648, 31616, 40976, 46584, 93168, 102768, 205536, 261600, 316160, 426304, 479616, 524112, 1048224, 1407856, 1699568, 1848384, 3696768, 4049376, 8098752, 9292544
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OFFSET
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1,2
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LINKS
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EXAMPLE
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f(4)=6: {}, {2}, {3}, {4}, {2,3}, {3,4}.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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Lionel Levine (levine(AT)ultranet.com)
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EXTENSIONS
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STATUS
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approved
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