A076316 Number of 4-colorable (i.e., chromatic number <= 4) simple graphs on n nodes.

1, 2, 4, 11, 33, 150, 985, 11390, 243791, 9965456, 753402410, 101344230844

Offset: 1

Author

Eric W. Weisstein, Oct 06 2002

Keywords

• nonn
• more

Links

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

Crossrefs

Cf. A033995, A076280, A076315, A076317, A076318, A076319, A076320, A076321.

Formula

a(n) = A076315(n) + A076280(n). - Andrew Howroyd, Dec 02 2018

Extensions

a(10)-a(11) from Andrew Howroyd, Dec 02 2018

a(12) from Sean A. Irvine, Apr 13 2025