OFFSET
1,2
COMMENTS
Column 3 of A221419
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 15*a(n-2)
EXAMPLE
Some solutions for n=4
..0..2..0....2..2..0....0..2..2....2..0..0....2..2..0....2..0..0....0..2..2
..2..2..0....0..2..0....0..2..0....0..2..2....0..0..2....0..2..0....0..2..0
..2..2..0....2..0..2....0..2..0....2..0..0....2..0..0....2..2..0....2..0..0
..0..0..2....0..2..0....2..2..0....0..2..2....2..2..0....2..2..0....2..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 15 2013
STATUS
approved