OFFSET
1,1
COMMENTS
Column 2 of A242549
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) +4*a(n-3) +4*a(n-4).
Empirical: G.f.: -2*x*(6+4*x+12*x^2+9*x^3) / ( (2*x^2+2*x-1)*(2*x^2+1) ). - R. J. Mathar, May 18 2014
EXAMPLE
Some solutions for n=4
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..0....1....1....1....1....1....1....1....0....0....1....1....0....0....1....1
..1....1....0....2....0....0....1....1....0....1....0....0....1....1....0....0
..2....1....0....1....0....2....2....0....1....2....0....2....0....0....1....2
..1....2....0....0....2....0....0....1....2....0....1....0....0....0....0....1
..1....1....1....1....0....1....2....0....2....0....2....0....0....2....0....1
..0....2....0....2....1....1....0....0....1....1....1....1....1....1....0....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 17 2014
STATUS
approved