OFFSET
1,1
COMMENTS
Column 4 of A183672.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..90
FORMULA
Empirical: a(n) = 28*a(n-1) - 322*a(n-2) + 1960*a(n-3) - 6769*a(n-4) + 13132*a(n-5) - 13068*a(n-6) + 5040*a(n-7).
Empirical g.f.: x*(41209 - 1027629*x + 10186855*x^2 - 50973255*x^3 + 134336776*x^4 - 174117636*x^5 + 84707280*x^6) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)*(1 - 7*x)). - Colin Barker, Apr 02 2018
EXAMPLE
Some solutions for 3 X 5:
..0..2..5..4..3....1..4..2..6..0....3..4..2..2..3....1..4..4..2..1
..6..4..1..2..3....1..6..0..4..2....2..3..3..5..2....5..2..2..4..5
..1..1..6..3..4....4..1..5..3..3....3..4..2..2..3....2..3..5..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2011
STATUS
approved