OFFSET
1,2
COMMENTS
Column 3 of A216338
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
EXAMPLE
Some solutions for n=4
..0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1....0..x..1
..x..2..x....x..2..x....x..2..x....x..0..x....x..2..x....x..2..x....x..2..x
..3..x..0....3..x..1....1..x..2....2..x..0....3..x..2....1..x..0....3..x..4
..x..1..x....x..3..x....x..3..x....x..3..x....x..4..x....x..1..x....x..5..x
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 04 2012
STATUS
approved