A360871 Number of unlabeled nonseparable (or 2-connected) multigraphs with n edges and degree >= 3 at each node, loops allowed.

0, 0, 2, 4, 9, 20, 44, 113, 329, 1044, 3622, 13544, 53596, 223084, 969158

Offset: 1

Author

Andrew Howroyd, Feb 25 2023

Keywords

• nonn
• more

Comments

A single-edge is considered to be nonseparable here.

Examples

			The a(3) = 2 multigraphs are:
  - a triple edge;
  - a single edge with a loop at each vertex.
		

Crossrefs

Row sums of A360870.

Cf. A002935, A360863, A360867.