A084284 Number of connected labeled 4-colorable (i.e., chromatic number <= 4) graphs on n nodes.

1, 1, 4, 38, 727, 26538, 1832900, 241187797, 60807843592, 29307734588670, 26725594885115575, 8457388648809892430

Offset

1,3

Links

Table of n, a(n) for n=1..12.

Eric Weisstein's World of Mathematics, n-Colorable Graph

Formula

Logarithmic transform of A084280. - Andrew Howroyd, Dec 02 2018

Crossrefs

Cf. A001832, A084274, A084280, A084283, A084285, A084286, A394474.

Sequence in context: A171779 A171203 A096332 * A084285 A084286 A001187

Adjacent sequences: A084281 A084282 A084283 * A084285 A084286 A084287

Keyword

nonn,hard,more

Author

Eric W. Weisstein, May 25 2003

Extensions

a(7)-a(11) from Andrew Howroyd, Dec 02 2018

a(12) from Sean A. Irvine, Mar 24 2026

Status

approved