OFFSET
1,3
COMMENTS
Column 2 of A215959.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..122
EXAMPLE
Some solutions for n=5
..0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x....0..x
..x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1....x..1
..1..x....1..x....2..x....2..x....2..x....1..x....2..x....1..x....2..x....1..x
..x..0....x..2....x..3....x..3....x..0....x..0....x..0....x..2....x..3....x..2
..0..x....0..x....1..x....0..x....1..x....2..x....0..x....3..x....4..x....2..x
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 28 2012
STATUS
approved