OFFSET
1,3
EXAMPLE
Some solutions for n=4
..0..1..0..0....0..0..0..0....0..1..0..0....1..0..0..1....1..1..1..0
..1..1..0..1....0..0..0..0....1..0..1..1....0..1..1..0....1..0..1..0
..0..0..1..1....0..0..0..0....0..1..1..0....0..1..1..0....1..1..1..0
..0..1..1..0....0..0..0..0....0..1..0..1....1..0..0..1....0..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin May 29 2011
STATUS
approved