OFFSET
1,1
COMMENTS
Column 3 of A188992.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 6*a(n-1) +a(n-2) -4*a(n-3) +2*a(n-4).
Empirical g.f.: x*(7 + 7*x - 6*x^2 + 2*x^3) / ((1 + x)*(1 - 7*x + 6*x^2 - 2*x^3)). - Colin Barker, May 01 2018
EXAMPLE
Some solutions for 4 X 3:
..1..0..0....0..1..0....0..0..0....1..1..0....0..0..0....1..0..0....1..0..0
..1..1..1....0..1..0....0..1..0....1..0..0....0..1..1....1..0..1....1..0..0
..0..0..0....1..1..0....1..1..1....0..1..1....1..0..0....0..1..1....0..0..0
..0..1..1....1..1..0....0..0..0....0..1..1....1..0..0....1..0..0....0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 15 2011
STATUS
approved