OFFSET
1,3
EXAMPLE
Some solutions for n=4
..3..3..2..2....3..3..3..3....1..1..0..0....3..3..2..2....0..0..2..2
..3..3..1..2....3..1..1..1....1..1..3..1....3..3..0..1....0..0..1..1
..2..1..1..0....3..1..0..0....0..3..3..1....2..0..0..1....2..1..0..0
..2..2..0..0....3..1..0..0....0..1..1..1....2..1..1..1....2..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 31 2012
STATUS
approved