A357446 Number of connected cubic simple graphs on 2n unlabeled nodes with chromatic index 4.

0, 0, 0, 2, 5, 34, 212, 1614, 14059, 144712, 1726497, 23550891, 361098825, 6137247735

Offset

2,4

Comments

In Table 1 of Goedgebeur and Ostergard (2021), the description says these count cubic graphs with no 3-edge-colorings. By Vizing's Theorem, if a cubic graph is not 3-edge-colorable then it has chromatic index 4. - Harry Richman, Oct 09 2025

Links

Table of n, a(n) for n=2..15.

Jan Goedgebeur and Patric R. J. Ostergard, Switching 3-Edge-Colorings of Cubic Graphs, arXiv:2105:01363 [math.CO], May 2021. See Table 1.

Brendan D. McKay and Gordon F. Royle, Constructing the cubic graphs on up to 20 vertices, Ars Combinatoria, 21A (1986) 129-140. See p. 138.

Crossrefs

Cf. A002851.

Sequence in context: A254429 A298945 A027303 * A371615 A356772 A307143

Adjacent sequences: A357443 A357444 A357445 * A357447 A357448 A357449

Keyword

nonn,more

Author

N. J. A. Sloane, Nov 08 2022

Extensions

Name corrected by Harry Richman, Oct 09 2025

Status

approved