OFFSET
1,2
COMMENTS
Diagonal of A219421
EXAMPLE
Some solutions for n=3
..1..1..0....0..0..0....1..1..0....0..0..1....0..0..0....0..0..1....0..0..0
..0..0..0....0..1..0....0..0..0....1..1..1....1..0..1....0..0..1....1..0..1
..1..0..1....0..0..1....0..1..1....1..0..0....1..1..1....1..0..0....0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Nov 19 2012
STATUS
approved