OFFSET
1,1
COMMENTS
Column 3 of A218084.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 4*a(n-2) - 5*a(n-4) - a(n-5) for n>6.
Empirical g.f.: 2*x*(1 - x)*(2 + 2*x - x^2 - 4*x^3 - x^4) / (1 - 2*x - 4*x^2 + 5*x^4 + x^5). - Colin Barker, Jul 24 2018
EXAMPLE
Some solutions for n=3:
..1..1..1....0..0..0....0..0..1....0..0..0....0..0..0....1..0..0....0..0..1
..1..1..1....0..0..0....0..0..1....0..0..0....0..0..0....1..0..0....0..0..0
..1..1..1....0..0..1....0..0..1....0..0..0....1..0..0....1..0..0....0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 20 2012
STATUS
approved