%I #15 May 22 2024 15:15:50
%S 0,0,0,0,0,0,0,4,9,23,42,70,105,154,226,326
%N Toroidal crossing number of complete graph.
%D Martin Gardner, Crossing Numbers. Ch. 11 in Knotted Doughnuts and Other Mathematical Entertainments. New York: W. H. Freeman, 1986.
%H Richard K. Guy, Tom Jenkyns, and Jonathan Schaer, <a href="https://doi.org/10.1016/S0021-9800(68)80063-8">Toroidal Crossing Number of Complete Graphw/a>, J. Comb. Th. 4, 376-390, 1968.
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ToroidalCrossingNumber.html">Toroidal Crossing Number</a>.
%e a(7) = 0 and a(8) = 4.
%K nonn,nice,more
%O 1,8
%A _Eric W. Weisstein_