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