OFFSET
1,2
COMMENTS
Column 2 of A183335.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + a(n-3) - a(n-4).
Empirical g.f.: x*(1 + 6*x + x^2 - 2*x^3) / (1 - x - 2*x^2 - x^3 + x^4). - Colin Barker, Feb 27 2018
EXAMPLE
Some solutions for 7 X 2:
..0..0....0..0....0..1....1..0....1..0....0..0....1..0....0..0....1..0....0..0
..1..1....0..0....0..0....0..0....0..1....1..0....0..0....1..1....0..0....1..1
..0..0....1..1....1..1....1..1....0..1....1..0....0..0....0..0....1..1....0..0
..1..1....0..0....0..0....0..0....0..0....0..0....1..0....0..0....0..0....0..0
..0..0....1..1....1..1....0..0....1..0....0..0....1..0....0..0....1..1....1..0
..0..0....0..0....0..0....0..0....1..0....0..0....0..0....0..0....0..0....1..0
..1..0....0..0....1..0....0..1....0..0....0..0....0..1....1..0....0..1....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 03 2011
STATUS
approved