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A360871
Number of unlabeled nonseparable (or 2-connected) multigraphs with n edges and degree >= 3 at each node, loops allowed.
2
0, 0, 2, 4, 9, 20, 44, 113, 329, 1044, 3622, 13544, 53596, 223084, 969158
OFFSET
1,3
COMMENTS
A single-edge is considered to be nonseparable here.
EXAMPLE
The a(3) = 2 multigraphs are:
- a triple edge;
- a single edge with a loop at each vertex.
CROSSREFS
Row sums of A360870.
Sequence in context: A024562 A087219 A214952 * A199296 A219229 A091620
KEYWORD
nonn,more
AUTHOR
Andrew Howroyd, Feb 25 2023
STATUS
approved