OFFSET
1,1
COMMENTS
Column 5 of A208637.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) - 10*a(n-2) + 4*a(n-3).
Conjectures from Colin Barker, Jul 05 2018: (Start)
G.f.: x*(16 - 49*x + 28*x^2) / ((1 - 2*x)*(1 - 4*x + 2*x^2)).
a(n) = (3*2^(1+n) + (11-2*sqrt(2))*(2-sqrt(2))^n + (2+sqrt(2))^n*(11+2*sqrt(2))) / 4.
(End)
EXAMPLE
Some solutions for n=4:
..0..0..1..1..0....0..1..1..0..0....0..1..0..0..1....0..1..1..0..0
..1..0..0..1..1....0..0..1..1..0....1..0..1..0..0....1..0..1..1..1
..1..1..0..0..0....1..0..0..1..1....1..0..1..1..1....0..1..0..0..1
..0..1..1..1..0....0..1..0..0..0....1..0..0..0..1....1..0..1..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2012
STATUS
approved