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A076323
Number of connected 4-colorable (i.e., chromatic number <= 4) simple graphs on n nodes.
7
1, 1, 2, 6, 20, 107, 801, 10227, 231228, 9708788, 743177051
OFFSET
1,3
LINKS
Maria Chudnovsky, Jan Goedgebeur, Oliver Schaudt, Mingxian Zhong, Obstructions for three-coloring graphs without induced paths on six vertices, arXiv preprint, arXiv:1504.06979 [math.CO], 2015-2018.
Eric Weisstein's World of Mathematics, n-Colorable Graph
FORMULA
Inverse Euler transform of A076316. - Andrew Howroyd, Dec 02 2018
MATHEMATICA
A076316 = Cases[Import["https://oeis.org/A076316/b076316.txt", "Table"], {_, _}][[All, 2]];
(* EulerInvTransform is defined in A022562 *)
EulerInvTransform[A076316] (* Jean-François Alcover, Sep 25 2019, updated Mar 17 2020 *)
KEYWORD
nonn,more
AUTHOR
Eric W. Weisstein, Oct 06 2002
EXTENSIONS
a(10)-a(11) from Andrew Howroyd, Dec 02 2018
STATUS
approved