OFFSET
1,1
COMMENTS
Column 2 of A221072.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 4*a(n-3) - 5*a(n-4) - 6*a(n-5).
Empirical g.f.: 2*x*(1 + x)*(1 + x - x^2 - 3*x^3) / (1 - 2*x - 2*x^2 - 4*x^3 + 5*x^4 + 6*x^5). - Colin Barker, Aug 03 2018
EXAMPLE
Some solutions for n=3:
..0..0....0..0....1..1....0..1....0..1....0..0....0..1....0..0....0..0....1..0
..1..0....0..1....0..0....0..0....1..0....0..0....0..1....1..1....1..0....0..0
..0..1....1..0....0..0....0..1....0..0....1..1....0..0....1..1....1..0....0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 31 2012
STATUS
approved