OFFSET
1,1
COMMENTS
Column 6 of A208637.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 15*a(n-2) + 10*a(n-3) - a(n-4).
Empirical g.f.: x*(32 - 129*x + 124*x^2 - 16*x^3) / ((1 - x)*(1 - 6*x + 9*x^2 - x^3)). - Colin Barker, Jul 05 2018
EXAMPLE
Some solutions for n=4:
..0..1..1..0..1..0....0..0..1..0..0..0....0..0..1..0..0..1....0..0..0..1..0..0
..1..0..1..0..1..1....1..0..1..1..1..0....1..0..1..1..0..0....1..1..0..1..1..0
..0..1..0..1..0..0....1..0..0..0..1..0....1..0..0..1..1..0....0..1..0..0..1..1
..0..1..0..1..1..1....0..1..1..0..1..1....1..1..0..0..1..0....1..0..1..0..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 29 2012
STATUS
approved