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%I #5 Dec 31 2023 16:28:55
%S 1,5,35,147,99,4719,102245,158015,71383,9493939,117578783,81161825,
%T 192225375,10034164575,176876744175,874129996575,506075261175,
%U 43691164214775,54585584382615,91204126883805,75171984897685,11189060829001575,315531515377844415,3726508102129106091
%N 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).
%H W. T. Tutte, <a href="https://doi.org/10.1137/0117044">On the enumeration of four-colored maps</a>, 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, A097985.
%K nonn,frac
%O 1,2
%A _N. J. A. Sloane_, Sep 21 2004
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