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 A006671 Chromatic number of cycle with n nodes. (Formerly M2269) 1
 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 3,1 COMMENTS The g.f. -(-3+3*z**3-z**4-3*z**5-z**6+4*z**7)/(z**6+z**5+z**2+z+1)/(z-1)**2 conjectured by Simon Plouffe in his 1992 dissertation is wrong. REFERENCES K. Al-Wahabi, R. Bari, F. Harary and D. Ullman, The edge-distinguishing chromatic number of paths and cycles, pp. 17-22 of Graph Theory in Memory of G. A. Dirac (Sandbjerg, 1985). Edited by L. D. Andersen et al., Annals of Discrete Mathematics, 41. North-Holland Publishing Co., Amsterdam-New York, 1989. N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS _Simon Plouffe_, Approximations de S\'{e}ries G\'{e}n\'{e}ratrices et Quelques Conjectures, Dissertation, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. _Simon Plouffe_, 1031 Generating Functions and Conjectures, Universit\'{e} du Qu\'{e}bec \`{a} Montr\'{e}al, 1992. CROSSREFS Sequence in context: A216194 A179847 A035936 * A046074 A068048 A176994 Adjacent sequences:  A006668 A006669 A006670 * A006672 A006673 A006674 KEYWORD nonn AUTHOR STATUS approved

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