OFFSET
1,1
COMMENTS
Column 4 of A228683
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) -2*a(n-2) -8*a(n-3).
Empirical: G.f. -8*x*(-1+x+x^2) / ( 1-6*x+2*x^2+8*x^3 ). - R. J. Mathar, Aug 31 2013
EXAMPLE
Some solutions for n=4
..0..0..1..0....0..1..0..1....1..0..0..0....0..0..0..1....1..0..0..1
..0..0..0..0....0..0..0..1....0..0..0..1....1..0..0..0....1..0..0..0
..1..0..1..0....1..0..0..0....0..0..0..1....1..0..0..1....0..0..0..0
..1..0..1..0....0..0..0..0....1..0..0..1....1..0..0..0....1..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 30 2013
STATUS
approved