OFFSET
1,1
COMMENTS
Column 4 of A232335
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) -9*a(n-2) -8*a(n-3) -4*a(n-4).
Empirical: G.f.: -2*x*(-3+5*x+8*x^2+4*x^3) / ( 1-7*x+9*x^2+8*x^3+4*x^4 ). - R. J. Mathar, Nov 24 2013
EXAMPLE
Some solutions for n=7
..0..1..2..1....2..1..2..1....0..1..0..2....2..1..2..1....2..1..0..2
..2..1..0..2....0..1..0..2....2..1..0..2....0..1..2..1....2..1..0..1
..2..1..0..2....0..1..0..1....0..2..1..0....0..1..2..1....2..1..2..1
..2..1..0..2....2..1..2..1....1..0..1..0....0..1..0..2....0..1..0..2
..0..1..0..2....0..1..0..2....1..2..1..2....0..2..0..2....0..2..1..2
..2..1..0..2....0..2..1..0....1..2..1..0....0..1..0..1....1..0..1..0
..0..2..1..0....1..2..1..0....1..0..2..1....2..1..2..1....2..0..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 22 2013
STATUS
approved