OFFSET
1,3
COMMENTS
Row 4 of A187046
FORMULA
Empirical: a(n) = 380*n^2 - 2568*n + 4388 for n>5
EXAMPLE
Some solutions for 4X4
..0..0..4..0....0..0..0..0....0..0..1..0....0..0..3..0....0..1..0..0
..0..0..0..3....4..0..1..0....0..3..0..0....0..2..0..0....0..0..3..0
..0..0..2..0....0..0..0..2....2..0..0..0....4..0..0..0....0..0..0..2
..0..0..0..1....0..0..3..0....0..0..0..4....0..0..0..1....4..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 02 2011
STATUS
approved