OFFSET
1,2
COMMENTS
Column 1 of A185487.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 3*a(n-1) + a(n-2) - 5*a(n-3) + 3*a(n-4) - 2*a(n-6) for n>7.
Empirical g.f.: 2*x^2*(15 - 7*x - 12*x^2 + 2*x^3 - 4*x^4 - 2*x^5) / (1 - 3*x - x^2 + 5*x^3 - 3*x^4 + 2*x^6). - Colin Barker, Feb 27 2018
EXAMPLE
Some solutions for 3 X 2:
..1..1....1..0....1..0....1..1....0..1....0..0....0..1....1..1....1..1....1..0
..0..0....0..0....1..0....1..1....0..0....0..0....0..0....1..1....0..0....0..0
..1..1....1..0....0..0....0..0....0..1....0..0....1..1....1..1....1..0....1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 28 2011
STATUS
approved