

A218090


Number of unlabeled pointdetermining bipartite graphs on n vertices.


3



1, 1, 1, 1, 2, 3, 8, 17, 63, 224, 1248, 8218, 75992, 906635, 14447433, 303100595, 8415834690, 309390830222, 15105805368214, 982300491033887
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OFFSET

0,5


COMMENTS

A graph is pointdetermining if no two vertices have the same set of neighbors. This kind of graph is also called a mating graph.


LINKS

Table of n, a(n) for n=0..19.
Ira Gessel and Ji Li, Enumeration of pointdetermining graphs, arXiv:0705.0042 [math.CO]
Andy Hardt, Pete McNeely, Tung Phan, and Justin M. Troyka, Combinatorial species and graph enumeration, arXiv:1312.0542 [math.CO].


EXAMPLE

Consider n = 3. The triangle graph is pointdetermining, but it is not bipartite, so it is not counted in a(3). The graph *** is bipartite, but it is not pointdetermining (the vertices on the two ends have the same neighborhood), so it is also not counted in a(3). The only graph counted in a(3) is the graph ** *.  Justin M. Troyka, Nov 27 2013


CROSSREFS

Cf. A006024, A004110 (labeled and unlabeled pointdetermining graphs).
Cf. A092430, A004108 (labeled and unlabeled connected pointdetermining graphs).
Cf. A232699 (labeled pointdetermining bipartite graphs).
Cf. A232700, A088974 (labeled and unlabeled connected pointdetermining bipartite graphs).
Sequence in context: A290383 A099960 A324963 * A101182 A009207 A290878
Adjacent sequences: A218087 A218088 A218089 * A218091 A218092 A218093


KEYWORD

nonn,more


AUTHOR

Andy Hardt, Oct 20 2012


STATUS

approved



