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).

1, 4, 24, 88, 52, 2176, 41344, 55936, 22080, 2561280, 27617280, 16570368, 34061312, 1540980736, 23512383488, 100462002176, 50231001088, 3741530783744, 4029340844032, 5798319751168, 4112761683968, 526433495547904, 12757611732533248, 129398633287122944

Offset: 1

Author

N. J. A. Sloane, Sep 21 2004

Keywords

• nonn
• frac

Examples

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

Links

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

Crossrefs

Cf. A000356, A000309, A097982.