OFFSET
1,3
COMMENTS
Column 1 of A195892
EXAMPLE
Some solutions for n=4
..0........0........0........0........0........0........0........0
..0.0.....-1.1.....-1.1......0.0.....-1.1......0.0......1-1......1-1
..0.0.0....0.0.0....0.0.0...-1.1.0....0.0.0....0-1.1...-1.1.0....0.0.0
..0.0.0.0..1-1.0.0..1-1.0.0..1-1.0.0..1-1.0.0..0.1-1.0..0.0.0.0.-1.1.0.0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 24 2011
STATUS
approved