OFFSET
4,4
COMMENTS
Some lower bounds: a(13) >= 272, a(14) >= 2, a(15) >= 360, a(16) >= 7, a(17) >= 7532, a(18) >= 2, a(19) >= 069 and a(20) >= 4.
LINKS
O. Aichholzer, F. Aurenhammer and H. Krasser, On the crossing number of complete graphs, Computing, 76:165-176, 2006. [alternative link]
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Don Pedro Esq. (info(AT)servierlaboratories.org), Feb 09 2008
STATUS
approved