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

6,4

Comments

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

Links

Table of n, a(n) for n=6..28.

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.

Prog

(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

Crossrefs

Column sums of A339072.

Cf. A002880, A006290, A010355, A338414.

Sequence in context: A124082 A056655 A341810 * A332971 A292033 A288501

Adjacent sequences: A338508 A338509 A338510 * A338512 A338513 A338514

Keyword

nonn,more

Author

Andrew Howroyd, Oct 31 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

Status

approved