OFFSET
1,1
COMMENTS
Column 2 of A183483.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 3*a(n-1) + 12*a(n-3) - 18*a(n-4) - 36*a(n-6).
Empirical g.f.: 3*x*(1 + 2*x - 2*x^2 - 6*x^3 - 12*x^4 - 12*x^5) / ((1 - 6*x^3)*(1 - 3*x - 6*x^3)). - Colin Barker, Mar 29 2018
EXAMPLE
Some solutions for 4 X 2.
..2..2....2..2....1..1....0..0....2..2....0..0....0..0....2..2....0..0....1..1
..0..0....2..2....0..2....0..0....1..1....1..1....2..0....0..0....2..2....1..1
..1..1....0..0....2..1....1..1....0..0....1..1....2..0....2..2....1..1....2..2
..0..0....1..1....2..2....0..0....2..2....1..1....0..0....2..2....1..1....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2011
STATUS
approved