A097872 Numerator 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, 5, 35, 147, 99, 4719, 102245, 158015, 71383, 9493939, 117578783, 81161825, 192225375, 10034164575, 176876744175, 874129996575, 506075261175, 43691164214775, 54585584382615, 91204126883805, 75171984897685, 11189060829001575, 315531515377844415, 3726508102129106091

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, A097985.