cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A373922 Number of lattices on n unlabeled nodes, up to duality.

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%I A373922 #23 Jul 02 2024 08:19:35
%S A373922 1,1,1,1,2,4,11,33,129,577,3113,19092,132318,1011665
%N A373922 Number of lattices on n unlabeled nodes, up to duality.
%C A373922 Number of nonisomorphic lattices on n nodes, when from each pair of dual lattices only one is counted.
%H A373922 Volker Gebhardt and Stephen Tawn, <a href="https://research-data.westernsydney.edu.au/published/ff5d9c10519311ecb15399911543e199/">Catalogue of unlabelled lattices on up to 16 elements</a>, Western Sydney University (2018).
%F A373922 a(n) = (A006966(n) + A373894(n)) / 2.
%e A373922 a(5)=4: These are the four lattices. The dual of the last one is not counted.
%e A373922   o      o        o       o
%e A373922   |     / \      /|\      |
%e A373922   o    o   |    o o o     o
%e A373922   |    |   o     \|/     / \
%e A373922   o    o   |      o     o   o
%e A373922   |     \ /              \ /
%e A373922   o      o                o
%e A373922   |
%e A373922   o
%K A373922 nonn,hard,more
%O A373922 0,5
%A A373922 _Jukka Kohonen_, Jun 30 2024