OFFSET
1,2
COMMENTS
Column 4 of A221273
EXAMPLE
Some solutions for n=4
..0..2..2..0....0..2..0..2....0..2..2..2....0..2..2..0....0..2..2..2
..2..0..0..2....0..0..2..0....0..0..0..0....2..0..2..0....0..0..0..0
..0..2..2..0....2..2..0..2....2..0..2..0....0..2..0..2....0..2..2..2
..0..2..2..0....2..0..0..2....2..2..2..0....0..2..2..0....0..0..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 08 2013
STATUS
approved