OFFSET
1,1
COMMENTS
Row 7 of A208085.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - 3*a(n-3) + a(n-4).
Conjectures from Colin Barker, Jun 28 2018: (Start)
G.f.: 18*x*(12 - 8*x - 17*x^2 + 7*x^3) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)).
a(n) = (9/5)*2^(1-n)*(2^n*(15+2*(-1)^n) + (9-4*sqrt(5))*(3-sqrt(5))^n + (3+sqrt(5))^n*(9+4*sqrt(5))).
(End)
EXAMPLE
Some solutions for n=4:
..0..1..0..0..1....0..0..0..1..0....0..1..0..0..1....0..0..0..1..1
..1..1..1..1..1....0..1..0..1..0....1..1..1..1..1....0..1..0..1..0
..1..1..1..1..1....1..0..1..0..1....1..1..1..1..1....1..0..1..0..1
..1..0..1..0..1....1..0..1..0..1....0..1..0..1..0....0..0..0..0..0
..0..1..0..1..0....0..1..0..1..0....1..0..1..0..1....0..0..0..0..0
..1..1..1..1..1....0..1..0..1..0....0..0..0..0..0....1..1..1..1..1
..1..1..1..1..1....1..0..1..0..1....0..0..0..0..0....1..1..1..1..1
..1..0..1..0..1....0..0..0..0..0....1..0..1..1..0....0..0..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 23 2012
STATUS
approved