OFFSET
1,1
COMMENTS
Column 2 of A183429.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n)=4*a(n-1) + a(n-3) - 4*a(n-4).
Empirical g.f.: x*(3 - 3*x - 4*x^2 - 2*x^3) / ((1 - x)*(1 - 4*x)*(1 + x + x^2)). - Colin Barker, Mar 29 2018
EXAMPLE
Some solutions for 4 X 2:
..1..2....2..2....0..1....2..1....0..2....1..1....0..0....2..1....1..1....0..2
..0..2....2..2....0..1....1..2....0..0....1..2....0..1....0..1....1..2....1..0
..1..2....2..2....0..1....1..2....1..2....0..2....0..0....2..2....2..2....0..0
..1..1....2..2....0..1....2..1....1..0....1..2....1..0....2..1....2..1....1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2011
STATUS
approved