A338511 Number of unlabeled 3-connected graphs with n edges.

1, 0, 1, 3, 4, 7, 22, 51, 152, 501, 1739, 6548, 26260, 110292, 483545, 2198726, 10327116, 49965520, 248481062, 1267987437, 6630660484, 35492360163, 194283212876

Offset: 6

Author

Andrew Howroyd, Oct 31 2020

Keywords

• nonn
• more

Comments

The smallest 3-connected graph is the complete graph on 4 vertices which has 6 edges.

Links

• Hugo Pfoertner, 3-connected graphs for n<=18 edges, list in PARI-readable format.
• R. W. Robinson, Tables of 2-Connected and 3-Connected Graphs by Nodes and Edges, Table VI, pages 19-27.

Crossrefs

Column sums of A339072.

Cf. A002880, A006290, A010355, A338414.

Programs

PARI

\\ It is assumed that the 3cc.gp file (from the linked zip archive) has been read before, i.e., \r [path]3cc.gp
for(k=1,#ThreeConnectedData,print1(#ThreeConnectedData[k],", "));
\\ printing of the graphs for n <= 9
print(ThreeConnectedData[6..9]) \\ Hugo Pfoertner, Dec 11 2020

Extensions

a(17)-a(25) from Hugo Pfoertner using data from Robinson's tables, Nov 20 2020

a(26)-a(28) from Andrew Howroyd using data from Robinson's tables, Nov 24 2020