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