OFFSET
1,1
COMMENTS
Column 3 of A189650.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 9*a(n-1) - 6*a(n-2) - 8*a(n-3) + 16*a(n-4).
Empirical g.f.: x*(3 + 6*x - 16*x^2 + 16*x^3) / (1 - 9*x + 6*x^2 + 8*x^3 - 16*x^4). - Colin Barker, May 02 2018
EXAMPLE
Some solutions for 4 X 3:
..0..1..2....1..0..2....1..0..4....4..0..2....0..2..1....0..3..4....1..0..2
..7..5..4....3..8..5....3..2..5....3..5..1....3..4..5....1..2..7....3..6..5
..6..3.10....6..9..4...10..6..7...10..6..8....7..9..8....6..5.10....7..8..4
..9..8.11....7.11.10....9..8.11....9.11..7...10..6.11....9..8.11....9.10.11
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 24 2011
STATUS
approved