OFFSET
1,1
COMMENTS
Column 1 of A202601.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) +7*a(n-2) +2*a(n-3) -a(n-4).
Empirical g.f.: 6*x*(21 + 43*x + 11*x^2 - 6*x^3) / (1 - 2*x - 7*x^2 - 2*x^3 + x^4). - Colin Barker, Jun 01 2018
EXAMPLE
Some solutions for n=3:
..0..1..1....1..0..1....1..1..1....1..0..0....0..1..0....1..1..0....1..1..0
..1..0..0....1..1..1....1..0..1....0..1..1....1..1..1....0..1..1....1..0..1
..0..1..1....0..1..1....1..1..1....1..0..1....0..1..1....1..0..1....1..1..1
..1..1..0....1..1..1....1..1..1....1..1..0....1..0..1....0..1..1....0..1..1
..1..0..0....0..1..1....1..0..1....1..1..1....1..0..1....0..1..0....1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 21 2011
STATUS
approved