A137237 - OEIS

%I #6 May 15 2020 04:40:13

%S 1,1,1,1,1,1,5,3

%N Number of non-isomorphic drawings of K_n with minimum crossings.

%C Entry for n=9 stated to be "about 200" in reference.

%C The paper does not actually show the five drawings of K_7, the three drawings of K_8, or the "about 200" drawings of K_9. Nor does it explain how these numbers were arrived at, or prove that there is only one drawing for K<7.

%H P. Erdos and R. K. Guy, <a href="http://links.jstor.org/sici?sici=0002-9890%28197301%2980%3A1%3C52%3ACNP%3E2.0.CO%3B2-1">Crossing Number Problems</a>, The American Mathematical Monthly, Vol. 80, No. 1. (1973), pp. 52-58.

%K hard,more,nonn

%O 1,7

%A Jonathan Schneider (jschne9(AT)uic.edu), Mar 08 2008