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 A097875 Denominator of J(n) = A000356(n)/A000309(n) (average number of 4-colorings of rank 0 in a rooted nonseparable map which is trivalent and has 2n nodes. 0
 1, 4, 24, 88, 52, 2176, 41344, 55936, 22080, 2561280, 27617280, 16570368, 34061312, 1540980736, 23512383488, 100462002176, 50231001088, 3741530783744, 4029340844032, 5798319751168, 4112761683968, 526433495547904, 12757611732533248, 129398633287122944 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 REFERENCES W. T. Tutte, On the enumeration of four-colored maps, SIAM J. Appl. Math., 17 (1969), 454-460. LINKS EXAMPLE 1, 5/4, 35/24, 147/88, 99/52, 4719/2176, 102245/41344, ... CROSSREFS Cf. A000356, A000309, A097982. Sequence in context: A210569 A005561 A061612 * A212681 A026694 A026967 Adjacent sequences:  A097872 A097873 A097874 * A097876 A097877 A097878 KEYWORD nonn,frac AUTHOR N. J. A. Sloane, Sep 21 2004 STATUS approved

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Last modified December 11 12:33 EST 2019. Contains 329916 sequences. (Running on oeis4.)