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%I M0700 #56 Sep 18 2021 08:56:15
%S 1,1,1,1,2,3,5,8,15,26,47,82,151,269,494,891,1639,2978,5483,10006,
%T 18428,33749,62162,114083,210189,386292,711811,1309475,2413144,
%U 4442221,8186962,15077454,27789108,51193086,94357143,173859936,320462062,590555664,1088548290,2006193418,3697997558,6815841849,12563729268,23157428823,42686759863,78682454720,145038561665,267348052028,492815778109,908414736485
%N Number of unlabeled distributive lattices on n nodes.
%D P. D. Lincoln, personal communication.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H Jukka Kohonen, <a href="/A006982/b006982.txt">Table of n, a(n) for n = 0..60</a>
%H R. Belohlavek and V. Vychodil, <a href="http://belohlavek.inf.upol.cz/publications/BeVy_Rls12.pdf">Residuated lattices of size <=12</a>, Order 27 (2010) 147-161, Table 6; DOI:<a href="https://doi.org/10.1007/s11083-010-9143-7">10.1007/s11083-010-9143-7</a>; <a href="https://math.chapman.edu/~jipsen/finitestructures/cirl/reslat12.pdf">Extended version</a>.
%H Aaron Chan, Erik Darpö, Osamu Iyama, and René Marczinzik, <a href="https://arxiv.org/abs/2012.11927">Periodic trivial extension algebras and fractionally Calabi-Yau algebras</a>, arXiv:2012.11927 [math.RT], 2020.
%H M. Erné, J. Heitzig and J. Reinhold, <a href="https://doi.org/10.37236/1641">On the number of distributive lattices</a>, Electronic Journal of Combinatorics, 9 (2002), #R24.
%H D. J. Greenhoe, <a href="https://peerj.com/preprints/520v1.pdf">MRA-Wavelet subspace architecture for logic, probability, and symbolic sequence processing</a>, 2014.
%H J. Heitzig and J. Reinhold, <a href="http://dx.doi.org/10.1023/A:1006431609027">The number of unlabeled orders on fourteen elements</a>, Order 17 (2000) no. 4, 333-341.
%H J. Heitzig and J. Reinhold, <a href="http://www-ifm.math.uni-hannover.de/forschung/preprintsifm.html">Counting finite lattices</a>, preprint no. 298, Institut für Mathematik, Universität Hanover, Germany, 1999.
%H J. Heitzig and J. Reinhold, <a href="http://dx.doi.org/10.1007/PL00013837">Counting finite lattices</a>, Algebra Universalis, 48 (2002), 43-53.
%H Institut f. Mathematik, Univ. Hanover, <a href="http://www-ifm.math.uni-hannover.de/html/preprints.phtml">Erne/Heitzig/Reinhold papers</a>
%H P. Jipsen, <a href="https://math.chapman.edu/~jipsen/tikzsvg/planar-distributive-lattices15.html">Planar distributive lattices up to size 15</a> (illustration of a(1..15)), personal web page, March 2014.
%H P. Jipsen and N. Lawless, <a href="http://math.chapman.edu/~jipsen/preprints/JipsenLawlessModularLattices20130905.pdf">Generating all finite modular lattices of a given size</a>, 2013.
%H Jukka Kohonen, <a href="https://doi.org/10.1007/s11083-021-09569-0">Cartesian lattice counting by the vertical 2-sum</a>, Order (2021); see also on <a href="https://arxiv.org/abs/2007.03232">arXiv</a>, arXiv:2007.03232 [math.CO], 2020.
%Y Cf. A006981, A006966, A343161.
%K hard,nonn,nice
%O 0,5
%A _N. J. A. Sloane_
%E 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.