OFFSET
1,4
COMMENTS
An intercalate is a 2 X 2 subsquare of a Latin square. a(10) >= 125, a(11) >= 172, a(12) >= 324.
REFERENCES
I. Wanless, Private communication, 2003.
LINKS
R. Bean, Critical sets in Latin squares and associated structures, Ph.D. Thesis, The University of Queensland, 2001.
K. Heinrich and W. Wallis, The maximum number of intercalates in a Latin square, Combinatorial Math. VIII, Proc. 8th Australian Conf. Combinatorics, 1980, 221-233.
FORMULA
If n is a power of 2, a(n) = n^2*(n-1)/4; if n is one less than a power of 2, a(n) = n*(n-1)*(n-3)/4.
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
Richard Bean, Feb 17 2004
STATUS
approved