OFFSET
1,1
COMMENTS
Column 1 of A185467.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = a(n-1) + 2*a(n-2) + 3*a(n-3) + 2*a(n-4) for n>5.
Empirical g.f.: 2*x*(8 + 9*x + 13*x^2 + 5*x^3 + 2*x^4) / (1 - x - 2*x^2 - 3*x^3 - 2*x^4). - Colin Barker, Apr 15 2018
EXAMPLE
Some solutions for 3 X 2:
..0..1....0..0....1..0....1..1....0..1....1..0....0..0....0..0....1..1....1..0
..1..0....0..1....0..1....1..0....1..0....1..1....1..0....1..1....0..1....0..1
..0..1....1..1....0..0....0..0....1..0....1..0....1..1....0..1....1..0....1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 28 2011
STATUS
approved