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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

%I

%S 1,4,24,88,52,2176,41344,55936,22080,2561280,27617280,16570368,

%T 34061312,1540980736,23512383488,100462002176,50231001088,

%U 3741530783744,4029340844032,5798319751168,4112761683968,526433495547904,12757611732533248,129398633287122944

%N 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.

%D W. T. Tutte, On the enumeration of four-colored maps, SIAM J. Appl. Math., 17 (1969), 454-460.

%e 1, 5/4, 35/24, 147/88, 99/52, 4719/2176, 102245/41344, ...

%Y Cf. A000356, A000309, A097982.

%K nonn,frac

%O 1,2

%A _N. J. A. Sloane_, Sep 21 2004

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Last modified November 28 04:31 EST 2021. Contains 349400 sequences. (Running on oeis4.)