OFFSET
1,2
EXAMPLE
Some solutions for n=4
..2..1..2..2....1..0..2..0....1..2..1..2....1..0..1..2....2..0..2..1
..1..0..1..0....0..2..1..2....2..0..1..0....0..2..0..0....0..2..0..1
..2..1..0..1....2..1..1..1....1..1..2..0....1..0..2..1....2..0..1..0
..2..0..1..2....0..2..1..2....2..0..0..2....2..0..1..2....1..1..0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 30 2012
STATUS
approved