A292790 Congruence-uniform lattices on n unlabeled nodes

1, 1, 1, 2, 4, 9, 22, 60, 174, 534, 1720, 5767, 20013, 71545

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