A052445 Number of simple unlabeled n-node graphs of connectivity 4.

0, 0, 0, 0, 1, 3, 21, 345, 13429, 1109105, 162318088, 39460518399

Offset: 1

Author

Eric W. Weisstein

Keywords

• nonn
• more
• hard

Examples

			The a(6) = 3 exactly-4-connected 6-node graphs are the complete graph K_6 with 1, 2, or 3 non-adjacent edges removed.
		

Links

• Brendan McKay, confusion over k-connected graphs, posting to Sequence Fans Mailing List, Jul 08 2015.
• Jens M. Schmidt, Data files in graph6 format
• Eric Weisstein's World of Mathematics, k-Connected Graph
• Eric Weisstein's World of Mathematics, Vertex Connectivity

Crossrefs

Cf. A052442, A052443, A052444, A086216, A086217, A259862.

Formula

a(n) = A086216(n) - A086217(n). - Andrey Zabolotskiy, Nov 20 2017

Extensions

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

a(8)-a(11) copied from A259862 by Andrey Zabolotskiy, Nov 20 2017

a(4)-a(5) corrected by Andrew Howroyd, Aug 28 2019

a(12) from Sean A. Irvine, Dec 12 2021