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A292852 Spherical congruence-uniform lattices on n unlabeled nodes 1
1, 1, 0, 1, 1, 2, 3, 8, 17, 45, 123, 367, 1148, 3792 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

A lattice is congruence-uniform if it can be constructed from the singleton-lattice by a sequence of interval doublings.  A lattice is spherical if its Möbius function between least and greatest element equals 1 or -1.

LINKS

Table of n, a(n) for n=1..14.

A. Day, Characterizations of finite lattices that are bounded-homomorphic images or sublattices of free lattices, Canadian Journal of Mathematics, 31 (1979), 617-631.

H. Mühle, On the lattice property of shard orders, arXiv:1708.02104 [math.CO], 2017.

CROSSREFS

Cf. A292790.

Sequence in context: A319566 A294450 A345243 * A148014 A148015 A148016

Adjacent sequences:  A292849 A292850 A292851 * A292853 A292854 A292855

KEYWORD

nonn,more

AUTHOR

Henri Mühle, Sep 25 2017

EXTENSIONS

a(13)-a(14) from Henri Mühle, Aug 29 2019

STATUS

approved

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Last modified July 26 16:44 EDT 2021. Contains 346294 sequences. (Running on oeis4.)