OFFSET
0,2
EXAMPLE
Some solutions for n=4
.....0........1........1........0........0........1........0........0...
....0.0......0.0......0.0......0.0......0.0......0.0......0.0......0.0..
...0.0.0....0.0.1....1.0.0....0.0.0....0.1.0....1.0.1....0.0.0....1.0.0.
..0.1.0.1..0.1.0.0..1.0.0.1..0.2.0.0..1.0.0.1..0.0.0.0..2.0.0.2..0.0.0.2
------
.....1........0........0........0........0........2........0........2...
....0.0......0.0......1.0......2.0......0.1......0.0......0.0......0.0..
...1.0.1....1.0.0....0.0.1....0.0.0....0.0.0....0.0.0....0.1.0....0.0.0.
..1.0.0.1..1.0.0.1..0.0.0.1..0.0.0.2..1.1.0.1..2.0.0.1..0.0.0.0..1.0.0.0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Oct 09 2009
STATUS
approved