OFFSET
1,3
COMMENTS
Diagonal of A215847.
EXAMPLE
Some solutions for n=4:
..0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x....0..x..1..x
..x..2..x..0....x..2..x..3....x..2..x..3....x..2..x..3....x..2..x..3
..3..x..4..x....1..x..4..x....1..x..0..x....4..x..0..x....4..x..0..x
..x..0..x..3....x..0..x..2....x..3..x..1....x..3..x..2....x..5..x..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 24 2012
EXTENSIONS
a(7)-a(12) from Andrew Howroyd, Jun 25 2017
STATUS
approved