OFFSET
1,1
COMMENTS
Column 1 of A185521.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 4*a(n-1) + 3*a(n-2) - 8*a(n-3).
Empirical g.f.: x*(31 + 19*x - 72*x^2) / (1 - 4*x - 3*x^2 + 8*x^3). - Colin Barker, Apr 16 2018
EXAMPLE
Some solutions for 3 X 2:
..0..2....0..0....2..1....0..1....2..0....1..0....1..2....2..0....1..1....1..0
..0..0....0..1....2..1....0..0....0..0....1..0....0..0....0..0....0..0....2..0
..1..0....0..2....0..0....1..1....0..2....1..0....0..1....0..0....1..2....2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 29 2011
STATUS
approved