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A292790 Congruence-uniform lattices on n unlabeled nodes 2
1, 1, 1, 2, 4, 9, 22, 60, 174, 534, 1720, 5767, 20013, 71545 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

A lattice is congruence-uniform if it can be constructed from the singleton-lattice by a sequence of interval doublings.

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

Sequence in context: A294281 A293854 A271078 * A278691 A159329 A159334

Adjacent sequences:  A292787 A292788 A292789 * A292791 A292792 A292793

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 September 18 01:39 EDT 2021. Contains 347504 sequences. (Running on oeis4.)