OFFSET
1,3
COMMENTS
Column 2 of A271194.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..14
EXAMPLE
Some solutions for n=4
.....0........0........0........0........0........0........0........0
....1.0......1.2......0.0......0.1......1.2......1.2......0.1......0.1
...0.0.1....2.2.1....1.2.0....2.1.2....1.1.1....0.1.1....1.1.2....2.2.2
..1.1.2.1..2.0.0.1..2.2.1.1..2.1.2.0..2.1.1.1..0.1.1.2..0.1.0.1..2.1.0.2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 01 2016
STATUS
approved