OFFSET
1,3
EXAMPLE
Some solutions for n=4
..0..0..1..1....0..0..1..0....0..0..1..0....0..0..1..2....0..0..0..0
..0..0..2..1....0..1..1..0....0..0..1..0....0..1..1..2....0..1..1..1
..1..2..2..1....1..1..2..2....1..1..1..2....1..1..0..0....0..1..2..2
..1..1..1..1....0..0..2..2....0..0..2..2....2..2..0..0....0..1..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 29 2012
STATUS
approved