OFFSET
1,2
COMMENTS
Column 3 of A230068
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) +14*a(n-2) -8*a(n-3).
Empirical: G.f.: -9*x^2*(-1+2*x) / ( (2*x+1)*(4*x^2-9*x+1) ). - R. J. Mathar, Mar 21 2016
EXAMPLE
Some solutions for n=4
..0..1..0....2..0..2....1..2..1....0..2..0....0..1..0....0..0..0....0..2..0
..1..2..0....2..0..2....0..1..0....2..2..0....1..2..1....2..2..2....0..2..0
..0..2..1....2..2..2....0..1..0....0..0..0....1..2..0....1..2..0....2..2..0
..0..1..0....0..0..0....1..2..1....2..2..2....0..1..0....0..1..0....0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 08 2013
STATUS
approved