OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) + 2*a(n-3) - 4*a(n-4) - a(n-6) for n>9.
Empirical g.f.: x*(2 + 2*x - 3*x^2 + 6*x^3 - 8*x^5 + 5*x^6 - 4*x^7 + 2*x^8) / (1 - 2*x - x^3)^2. - Colin Barker, Feb 10 2019
EXAMPLE
Some solutions for n=4:
..0..1..0. .0..1..0. .0..1..1. .0..0..1. .0..1..1. .0..1..0. .0..0..1
..0..0..1. .1..0..1. .0..0..0. .0..1..0. .1..1..0. .1..0..0. .1..1..0
..1..1..0. .0..1..1. .0..1..1. .1..0..1. .0..0..1. .0..0..1. .0..0..0
..0..1..0. .1..0..0. .1..0..0. .0..1..0. .1..1..0. .1..1..0. .1..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 08 2016
STATUS
approved