OFFSET
1,2
COMMENTS
Column 1 of A270509.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..28
EXAMPLE
Some solutions for n=4
.....0........0........1........1........1........1........0........0
....1.1......1.0......0.1......1.0......0.0......0.0......0.0......1.0
...0.0.0....0.0.0....1.0.0....0.0.0....0.0.1....1.0.0....0.0.1....0.0.0
..0.1.0.0..1.1.0.0..0.0.0.1..1.0.0.0..1.0.0.1..1.0.1.0..1.0.1.0..1.1.0.1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 18 2016
STATUS
approved