OFFSET
1,1
COMMENTS
Column 4 of A186472.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + 4*a(n-4) - 2*a(n-5) for n>13.
Empirical g.f.: x*(367 - 172*x - 288*x^2 + 1686*x^3 - 1920*x^4 + 196*x^5 - 604*x^6 + 1428*x^7 - 1350*x^8 + 1364*x^9 + 36*x^10 - 18*x^11 + 9*x^12) / ((1 - x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 18 2018
EXAMPLE
Some solutions for 3 X 5:
..0..0..0..1..1....1..2..0..2..0....1..2..0..0..0....2..0..0..0..0
..0..0..0..0..1....2..0..2..0..2....2..0..2..0..0....0..2..0..0..0
..2..0..0..0..0....0..2..0..2..1....0..2..0..2..0....0..0..2..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 22 2011
STATUS
approved