OFFSET
1,2
COMMENTS
Diagonal of A280859.
EXAMPLE
Some solutions for n=4
..0..1..1..2. .0..1..2..2. .0..1..1..0. .0..1..1..2. .0..1..2..0
..0..2..0..0. .0..1..0..1. .0..2..0..2. .0..2..0..0. .2..1..2..1
..1..2..1..2. .2..2..0..2. .1..2..1..2. .1..2..1..1. .2..0..0..1
..1..0..0..2. .0..1..1..2. .1..0..0..1. .1..0..0..2. .1..1..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 09 2017
STATUS
approved