OFFSET
1,1
COMMENTS
Column 2 of A183819.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 15*a(n-1) + 120*a(n-2) - 330*a(n-3).
Empirical g.f.: 2*x*(4 + 21*x - 67*x^2) / (1 - 15*x - 120*x^2 + 330*x^3). - Colin Barker, Apr 04 2018
EXAMPLE
Some solutions with upper left block zero for 5 X 3:
0 0 0 0 0 0 0 0 1 0 0 2 0 0 1 0 0 0 0 0 2
0 0 2 0 0 1 0 0 1 0 0 1 0 0 0 0 0 2 0 0 2
0 1 0 0 2 0 0 1 2 2 1 1 0 2 2 1 1 0 0 2 2
2 2 1 1 2 0 1 1 2 2 1 2 0 2 2 0 2 1 0 2 1
1 0 1 1 0 2 1 1 1 0 2 1 0 1 0 1 2 2 2 0 0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 07 2011
STATUS
approved