OFFSET
1,1
COMMENTS
Column 3 of A183662.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 21*a(n-1) - 175*a(n-2) + 735*a(n-3) - 1624*a(n-4) + 1764*a(n-5) - 720*a(n-6).
Empirical g.f.: 2*x*(1627 - 29172*x + 197411*x^2 - 622938*x^3 + 901512*x^4 - 466560*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)*(1 - 5*x)*(1 - 6*x)). - Colin Barker, Apr 02 2018
EXAMPLE
Some solutions for 3 X 4:
..2..4..2..5....3..3..4..1....2..4..1..4....1..3..1..4....2..3..1..5
..2..2..2..1....4..0..3..2....2..2..3..2....1..5..1..4....2..3..3..1
..3..3..3..4....1..5..2..3....4..2..3..2....3..1..3..2....2..3..1..5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2011
STATUS
approved