OFFSET
1,1
COMMENTS
Column 4 of A221666
EXAMPLE
Some solutions for n=3
..0..1..0..0....0..1..1..0....0..1..0..0....1..1..0..0....0..0..0..1
..1..0..1..1....1..1..0..1....1..1..0..0....0..0..0..1....0..0..0..1
..0..1..0..1....1..1..0..1....0..1..1..0....1..1..1..1....1..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 21 2013
STATUS
approved