OFFSET
1,1
COMMENTS
Column 1 of A183642.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4).
Conjectures from Colin Barker, Feb 27 2018: (Start)
G.f.: 4*x*(11 - 76*x + 158*x^2 - 96*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)).
a(n) = 2 + 2^(2+n) + 2*3^(1+n) + 4^(1+n).
(End)
EXAMPLE
Some solutions for 3 X 2:
..0..3....2..2....0..3....1..3....0..2....1..3....2..1....3..0....1..3....3..1
..3..0....0..2....0..3....0..2....1..3....1..1....2..1....0..3....2..0....1..1
..1..2....3..1....3..0....2..2....2..0....2..2....3..0....2..1....1..3....1..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 06 2011
STATUS
approved