OFFSET
1,1
COMMENTS
Column 3 of A205318.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 10*a(n-1) -24*a(n-2) +21*a(n-3) -6*a(n-4).
Empirical g.f.: 2*x*(2 - 3*x)*(14 - 25*x + 10*x^2) / ((1 - x)*(1 - 9*x + 15*x^2 - 6*x^3)). - Colin Barker, Jun 11 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..1....0..1..1..0....0..0..0..0....0..0..1..1....0..0..1..0
..1..1..1..1....1..1..0..0....0..1..1..0....0..1..1..0....0..1..1..1
..0..1..0..0....0..0..0..1....1..1..0..0....0..0..0..0....1..1..0..0
..0..0..0..1....0..1..1..1....1..0..0..1....0..1..1..0....1..0..0..1
..1..1..1..1....0..1..0..0....1..1..0..1....1..1..0..0....0..0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 25 2012
STATUS
approved