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A076322 Number of connected 3-colorable (i.e., chromatic number <= 3) simple graphs on n nodes. 7
1, 1, 2, 5, 17, 81, 519, 5218, 81677, 2014360, 76140741, 4303246908 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

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

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 A076315. - Andrew Howroyd, Dec 02 2018

MATHEMATICA

A076315 = Cases[Import["https://oeis.org/A076315/b076315.txt", "Table"], {_, _}][[All, 2]];

(* EulerInvTransform is defined in A022562 *)

EulerInvTransform[A076315] (* Jean-Fran├žois Alcover, Sep 25 2019, updated Mar 17 2020 *)

CROSSREFS

Cf. A005142, A076323, A076324, A076325, A076326, A076327, A076328.

Cf. A076279, A076315, A084269, A126737.

Sequence in context: A001186 A125282 A020125 * A098540 A079574 A032262

Adjacent sequences:  A076319 A076320 A076321 * A076323 A076324 A076325

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Oct 06 2002

EXTENSIONS

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

a(12) from Jinyuan Wang, Feb 23 2020

STATUS

approved

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Last modified May 14 22:40 EDT 2021. Contains 343909 sequences. (Running on oeis4.)