OFFSET
1,1
COMMENTS
Column 1 of A209897.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) +4*a(n-2).
Empirical G.f.: x*(7+6*x)/(1-4*x-4*x^2). [Colin Barker, Mar 15 2012]
EXAMPLE
Some solutions for n=4:
..0..1....0..1....0..0....0..0....0..0....0..0....0..0....0..1....0..0....0..1
..1..0....0..0....0..1....0..1....0..1....1..1....1..0....1..0....0..1....0..0
..1..0....2..0....0..0....0..1....1..0....1..0....1..0....1..0....1..0....2..2
..0..0....0..0....2..0....1..0....0..1....0..0....0..0....1..0....0..0....2..0
..2..2....2..2....0..0....1..1....0..0....2..2....0..2....0..1....1..0....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 14 2012
STATUS
approved