OFFSET
1,1
COMMENTS
Column 7 of A184039.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..118
FORMULA
Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 4*a(n-4).
Conjectures from Colin Barker, Apr 10 2018: (Start)
G.f.: x*(625 - 1238*x - 1253*x^2 + 2476*x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x^2)).
a(n) = 9*2^(n/2-1) + 9*2^(n-1) + 610 for n even.
a(n) = 9*2^(n-1) + 3*2^((n+1)/2) + 610 for n odd.
(End)
EXAMPLE
Some solutions for 3 X 8:
..2..2..2..2..2..2..2..1....0..0..3..2..0..2..0..2....2..3..2..3..1..3..2..3
..3..1..3..1..3..1..3..2....3..2..0..0..3..0..3..0....1..2..1..2..2..2..1..2
..2..2..2..2..2..2..2..1....0..0..3..2..0..2..0..2....2..3..2..3..1..3..2..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 08 2011
STATUS
approved