A086216 Number of 4-connected unlabeled n-node graphs.

0, 0, 0, 0, 1, 4, 25, 384, 14480, 1211735, 184649399, 47952362294

Offset: 1

Author

Eric W. Weisstein, Jul 12 2003

Keywords

• nonn
• hard
• more

Comments

The definition means that the connectivity is 4 or more.

Examples

			There are 4 different 4-connected graphs on 6 vertices. - _Dylan Thurston_, Jun 18 2009
		

Links

• Travis Hoppe and Anna Petrone, Integer sequence discovery from small graphs, arXiv preprint arXiv:1408.3644, [math.CO], 2014.
• Travis Hoppe and Anna Petrone, Integer sequence discovery from small graphs, Discr. Appl. Math. 201 (2016) 172-181.
• Eric Weisstein's World of Mathematics, k-Connected Graph

Crossrefs

See A052445 for exactly-4-connected graphs.

See A086217 for 5-connected graphs.

See A259862 for further information.

Formula

a(n) = A086217(n) + A052445(n). - Andrew Howroyd, Sep 04 2019

Extensions

Offset corrected by Dylan Thurston, Jun 18 2009

a(10) from the Encyclopedia of Finite Graphs (Travis Hoppe and Anna Petrone), Apr 11 2014

Minor edits by N. J. A. Sloane, Jul 08 2015 at the suggestion of Brendan McKay.

a(12) added by Georg Grasegger, Jan 07 2025