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Number of semimodular lattices on n nodes.
2

%I #15 Apr 18 2021 01:46:06

%S 1,1,1,1,2,4,8,17,38,88,212,530,1376,3693,10232,29231,85906,259291,

%T 802308,2540635,8220218,27134483,91258141,312324027,1086545705,

%U 3838581926

%N Number of semimodular lattices on n nodes.

%H P. Jipsen and N. Lawless, <a href="http://math.chapman.edu/~jipsen/preprints/JipsenLawlessModularLattices20130905.pdf">Generating all modular lattices of a given size</a>

%H J. Kohonen, <a href="http://arxiv.org/abs/1708.03750">Generating modular lattices up to 30 elements</a>, arXiv:1708.03750 [math.CO] preprint (2017).

%Y Cf. A006966 (number of lattices), A006981 (number of modular lattices).

%K nonn,more

%O 0,5

%A _Nathan Lawless_, Sep 15 2013

%E a(23)-a(25) from Kohonen (2017), by _Jukka Kohonen_, Aug 15 2017