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