A326215 Number of Hamiltonian unlabeled n-vertex graphs with loops.

0, 2, 0, 4, 20

Offset: 0

Author

Gus Wiseman, Jun 17 2019

Keywords

• nonn
• more

Comments

A graph is Hamiltonian if it contains a cycle passing through every vertex exactly once.

Examples

			Non-isomorphic representatives of the a(3) = 4 edge-sets:
  {12,13,23}
  {12,13,23,33}
  {12,13,22,23,33}
  {11,12,13,22,23,33}
		

Links

• Wikipedia, Hamiltonian path
• Gus Wiseman, Non-isomorphic representatives of the a(4) = 20 Hamiltonian graphs with loops.

Crossrefs

The labeled case is A326240.

The directed case is A326226 (with loops) or A326225 (without loops).

The case without loops A003216.

Cf. A000088, A006125, A057864, A283420, A326239.