OFFSET
1,1
COMMENTS
Column 1 of A210390.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 9*a(n-1) - 6*a(n-2) - 6*a(n-3).
Empirical g.f.: x*(73 - 60*x - 54*x^2) / (1 - 9*x + 6*x^2 + 6*x^3). - Colin Barker, Jul 15 2018
EXAMPLE
Some solutions for n=4:
..0..0....2..1....2..1....0..2....2..1....2..0....2..1....1..2....1..2....0..2
..2..1....0..0....1..1....2..0....0..0....1..0....0..0....0..1....0..2....0..1
..2..0....2..0....0..1....0..2....1..1....0..0....1..1....2..1....0..2....2..1
..1..0....0..2....2..2....0..1....1..2....1..0....1..0....2..0....2..2....1..0
..0..0....1..1....1..2....1..2....1..1....2..1....2..1....0..2....0..2....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 20 2012
STATUS
approved