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Search: id:A046907
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| A046907 |
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Number of isomorphism classes of irreducible posets with n labeled points. |
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+0
2
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| 1, 1, 1, 2, 7, 31, 184, 1351, 12524, 146468, 2177570, 41374407, 1008220289, 31559446774, 1269310589336, 65562045668340, 4345161435996517
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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J. A. Wright, There are 718 6-point topologies, quasi-orderings, and transgraphs, Notices Amer. Math. Soc., 17 (1970), p. 646, Abstract #70T-A106.
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LINKS
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Index entries for sequences related to posets
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FORMULA
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G.f.: A(x) = 2-1/B(x), where B(x) is g.f. of A000112. - Vladeta Jovovic (vladeta(AT)Eunet.yu), Jan 15 2006
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CROSSREFS
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Cf. A046908.
Sequence in context: A105216 A005977 A059037 this_sequence A091312 A118581 A102159
Adjacent sequences: A046904 A046905 A046906 this_sequence A046908 A046909 A046910
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KEYWORD
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nonn
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AUTHOR
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John A. Wright.
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EXTENSIONS
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More terms from Vladeta Jovovic (vladeta(AT)Eunet.yu), Jan 15 2006
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