OFFSET
1,2
EXAMPLE
Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..1..2..3....0..0..2..2....0..0..3..3....0..0..2..2....0..0..0..1
..0..1..4..6....0..3..4..4....0..1..3..4....0..0..2..4....0..0..0..2
..0..3..4..7....0..3..4..7....0..1..4..7....0..1..4..6....0..0..2..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 26 2011
STATUS
approved