OFFSET
1,2
COMMENTS
Column 4 of A216084
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..78
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....2..x..3..x....2..x..3..x....1..x..2..x....2..x..3..x
..x..1..x..2....x..4..x..5....x..4..x..1....x..3..x..1....x..1..x..0
..3..x..0..x....6..x..0..x....5..x..3..x....0..x..4..x....4..x..3..x
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Sep 01 2012
STATUS
approved