OFFSET
1,1
COMMENTS
Column 1 of A205836.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - a(n-2) + a(n-3).
Empirical g.f.: 3*x*(10 - 3*x + 3*x^2) / (1 - 4*x + x^2 - x^3). - Colin Barker, Jun 12 2018
EXAMPLE
Some solutions for n=4:
..0..0....2..1....1..2....2..1....2..0....2..0....1..0....1..0....1..1....1..2
..2..1....1..2....0..1....0..2....2..1....2..1....2..1....2..1....0..2....0..2
..1..2....0..0....2..2....1..0....0..2....0..2....1..2....0..2....2..0....2..0
..2..0....2..1....1..0....2..1....1..0....1..0....0..1....2..1....0..2....0..1
..1..2....0..2....2..1....1..0....0..1....2..1....0..2....0..2....1..0....2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 01 2012
STATUS
approved