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A137237
Number of non-isomorphic drawings of K_n with minimum crossings.
0
1, 1, 1, 1, 1, 1, 5, 3
OFFSET
1,7
COMMENTS
Entry for n=9 stated to be "about 200" in reference.
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.
LINKS
P. Erdos and R. K. Guy, Crossing Number Problems, The American Mathematical Monthly, Vol. 80, No. 1. (1973), pp. 52-58.
CROSSREFS
Sequence in context: A212481 A046270 A139207 * A369841 A152419 A322758
KEYWORD
hard,more,nonn
AUTHOR
Jonathan Schneider (jschne9(AT)uic.edu), Mar 08 2008
STATUS
approved