OFFSET
1,2
COMMENTS
Diagonal of A216031.
EXAMPLE
Some solutions for n=4
..x..0..x..1....x..0..x..1....x..0..x..1....x..0..x..1....x..0..x..1
..2..x..3..x....0..x..2..x....2..x..3..x....2..x..3..x....2..x..3..x
..x..3..x..4....x..1..x..0....x..3..x..0....x..4..x..2....x..1..x..4
..3..x..0..x....3..x..0..x....4..x..2..x....5..x..2..x....1..x..0..x
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 30 2012
STATUS
approved