OFFSET
1,2
COMMENTS
Column 1 of A183501
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n)=2*a(n-1)+2*a(n-3)-4*a(n-4).
Empirical G.f.: x*(1+x)*(1-2*x^2)/(1-2*x)/(1-2*x^3). [Colin Barker, Feb 23 2012]
EXAMPLE
All solutions for 3X1
..0....1....0....0....0....1....2....2
..2....0....1....1....2....2....1....0
..1....1....2....0....0....0....0....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Jan 05 2011
STATUS
approved