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A247659
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Number of down-arrow-indecomposable topologies on n labeled points.
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1
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1, 3, 22, 292, 6120, 193594, 9070536, 622336756, 61915861962, 8846814822932, 1798543906246948, 515674104905890202, 206833212761446463192, 115198617558900993580396, 88503974769306037986089170, 93233054587165663487254293572
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OFFSET
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1,2
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LINKS
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FORMULA
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MATHEMATICA
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A000798 = {1, 1, 4, 29, 355, 6942, 209527, 9535241, 642779354, 63260289423, 8977053873043, 1816846038736192, 519355571065774021, 207881393656668953041, 115617051977054267807460, 88736269118586244492485121, 93411113411710039565210494095, 134137950093337880672321868725846, 261492535743634374805066126901117203};
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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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