OFFSET
1,1
COMMENTS
Diagonal of A226717
EXAMPLE
Some solutions for n=3
.-1..1..0...-1..0..0....1.-1..1....0..0..0....1.-1..1...-1.-1..0....0..1.-1
..1..0.-1....1..0..0...-1..0..1....0.-1..1....0.-1..0....1..0..0....0..0..1
.-1..0..1....1..0..1....1..0..0...-1..0..0....1..0..0...-1..0..0....1..0.-1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jun 15 2013
STATUS
approved