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Search: id:A006982
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| A006982 |
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Number of unlabeled distributive lattices with n elements.
(Formerly M0700)
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+0
5
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| 1, 1, 1, 1, 2, 3, 5, 8, 15, 26, 47, 82, 151, 269, 494, 891, 1639, 2978, 5483, 10006, 18428, 33749, 62162, 114083, 210189, 386292, 711811, 1309475, 2413144, 4442221, 8186962, 15077454, 27789108, 51193086, 94357143, 173859936, 320462062, 590555664, 1088548290, 2006193418, 3697997558, 6815841849, 12563729268, 23157428823, 42686759863, 78682454720, 145038561665, 267348052028, 492815778109, 908414736485
(list; graph; listen)
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OFFSET
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0,5
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REFERENCES
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J. Heitzig and J. Reinhold, Counting finite lattices, Algebra Universalis, 48 (2002), 43-53.
J. Heitzig and J. Reinhold, The number of unlabeled orders on fourteen elements, Order 17 (2000) no. 4, 333-341.
P. D. Lincoln, personal communication.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
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J. Heitzig and J. Reinhold, Counting finite lattices, preprint no. 298, Institut fuer Mathematik, Universitaet Hanover, Germany, 1999.
M. Erne, J. Heitzig and J. Reinhold, On the number of distributive lattices, Electronic Journal of Combinatorics, 9 (2002), #R24.
Institut f. Mathematik, Univ. Hanover, Erne/Heitzig/Reinhold papers
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CROSSREFS
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Cf. A006981, A006966.
Sequence in context: A058519 A151518 A082095 this_sequence A054539 A026702 A000047
Adjacent sequences: A006979 A006980 A006981 this_sequence A006983 A006984 A006985
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KEYWORD
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hard,nonn,nice
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms from Jobst Heitzig (heitzig(AT)math.uni-hannover.de), Feb 02 2001. These were computed by the same algorithm that was used to enumerate the posets on 14 elements.
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