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Search: id:A006056
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| A006056 |
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Number of labeled topologies with n points.
(Formerly M3615)
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+0
1
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| 1, 1, 4, 26, 255, 3642, 75606, 2316169, 106289210, 7321773414, 748425136289, 111576624613588, 23864968806932886, 7225895692327786931, 3064182503223082011556, 1803904252801640389374494
(list; graph; listen)
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OFFSET
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0,3
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REFERENCES
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M. Erne', Struktur- und Anzahlformeln fuer Topologien auf Endlichen Mengen, Manuscripta Math., 11 (1974), 221-259.
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LINKS
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Herman Jamke (hermanjamke(AT)fastmail.fm), Mar 02 2008, Table of n, a(n) for n = 0..19
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FORMULA
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E.g.f.: A4(X)=exp(Z4(X)-1) where Z4(x) denotes the e.g.f. for A006058. - Herman Jamke (hermanjamke(AT)fastmail.fm), Mar 02 2008
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CROSSREFS
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Sequence in context: A052880 A090357 A056786 this_sequence A098620 A002465 A079473
Adjacent sequences: A006053 A006054 A006055 this_sequence A006057 A006058 A006059
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KEYWORD
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nonn,nice
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AUTHOR
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njas
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EXTENSIONS
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More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Mar 02 2008
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