OFFSET
1,3
COMMENTS
Column 1 of A271407.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..20
EXAMPLE
Some solutions for n=4
.....0........0........0........0........0........0........0........0
....0.1......1.1......0.1......1.1......0.0......1.0......1.1......1.0
...0.0.1....0.1.0....0.1.1....0.0.0....0.1.1....1.0.0....0.1.1....1.1.1
..0.0.1.0..0.1.0.1..0.0.1.1..0.1.0.1..0.1.1.0..1.1.0.0..0.0.0.1..1.0.1.0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 06 2016
STATUS
approved