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A006982 Number of unlabeled distributive lattices on n nodes.
(Formerly M0700)
7
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; refs; listen; history; text; internal format)
OFFSET

0,5

REFERENCES

P. D. Lincoln, personal communication.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Jukka Kohonen, Table of n, a(n) for n = 0..60

R. Belohlavek and V. Vychodil, Residuated lattices of size <=12, Order 27 (2010) 147-161, Table 6; DOI:10.1007/s11083-010-9143-7; Extended version.

Aaron Chan, Erik Darpö, Osamu Iyama, and René Marczinzik, Periodic trivial extension algebras and fractionally Calabi-Yau algebras, arXiv:2012.11927 [math.RT], 2020.

M. Erné, J. Heitzig and J. Reinhold, On the number of distributive lattices, Electronic Journal of Combinatorics, 9 (2002), #R24.

D. J. Greenhoe, MRA-Wavelet subspace architecture for logic, probability, and symbolic sequence processing, 2014.

J. Heitzig and J. Reinhold, The number of unlabeled orders on fourteen elements, Order 17 (2000) no. 4, 333-341.

J. Heitzig and J. Reinhold, Counting finite lattices, preprint no. 298, Institut für Mathematik, Universität Hanover, Germany, 1999.

J. Heitzig and J. Reinhold, Counting finite lattices, Algebra Universalis, 48 (2002), 43-53.

Institut f. Mathematik, Univ. Hanover, Erne/Heitzig/Reinhold papers

P. Jipsen, Planar distributive lattices up to size 15 (illustration of a(1..15)), personal web page, March 2014.

P. Jipsen and N. Lawless, Generating all finite modular lattices of a given size, 2013.

Jukka Kohonen, Cartesian lattice counting by the vertical 2-sum, Order (2021); see also on arXiv, arXiv:2007.03232 [math.CO], 2020.

CROSSREFS

Cf. A006981, A006966, A343161.

Sequence in context: A151518 A082095 A177486 * A054539 A026702 A000047

Adjacent sequences:  A006979 A006980 A006981 * A006983 A006984 A006985

KEYWORD

hard,nonn,nice

AUTHOR

N. J. A. Sloane

EXTENSIONS

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.

STATUS

approved

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Last modified October 17 17:21 EDT 2021. Contains 348065 sequences. (Running on oeis4.)