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A326223
Number of non-Hamiltonian unlabeled n-vertex digraphs (with loops).
8
1, 0, 7, 80, 2186
OFFSET
0,3
COMMENTS
A digraph is Hamiltonian if it contains a directed cycle passing through every vertex exactly once.
EXAMPLE
Non-isomorphic representatives of the a(2) = 7 digraph edge-sets:
{}
{11}
{12}
{11,12}
{11,21}
{11,22}
{11,12,22}
CROSSREFS
The labeled case is A326220.
The case without loops is A326222.
The undirected case is A246446 (without loops) or A326239 (with loops).
Hamiltonian unlabeled digraphs are A326226.
Unlabeled digraphs not containing a Hamiltonian path are A326224.
Sequence in context: A085606 A365817 A264691 * A058785 A373441 A171768
KEYWORD
nonn,more
AUTHOR
Gus Wiseman, Jun 15 2019
STATUS
approved