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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..11.

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-Fran├žois Alcover, Sep 25 2019, updated Mar 17 2020 *)

CROSSREFS

Cf. A005142, A076322, A076324, A076325, A076326, A076327, A076328.

Cf. A076280, A076316, A084269, A126738.

Sequence in context: A079455 A052433 A078566 * A241782 A268562 A287009

Adjacent sequences:  A076320 A076321 A076322 * A076324 A076325 A076326

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Oct 06 2002

EXTENSIONS

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

STATUS

approved

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Last modified May 12 10:12 EDT 2021. Contains 343821 sequences. (Running on oeis4.)