OFFSET
1,3
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 6*a(n-3) - 12*a(n-4) + 8*a(n-5) - 4*a(n-6) + 8*a(n-7).
Empirical g.f.: 2*x^3*(2 - 2*x + x^2 - 6*x^3) / ((1 - 2*x)*(1 - x - 2*x^3)^2). - Colin Barker, Feb 10 2019
EXAMPLE
Some solutions for n=4:
..0..1. .0..1. .0..1. .0..1. .0..0. .0..0. .0..0. .0..1. .0..0. .0..0
..1..1. .1..0. .0..1. .0..1. .1..1. .1..1. .1..1. .1..0. .1..1. .1..1
..0..0. .0..0. .1..1. .0..0. .1..0. .0..0. .0..1. .1..1. .0..1. .1..0
..1..1. .1..1. .0..0. .1..1. .0..1. .1..0. .1..0. .0..0. .0..1. .1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 06 2016
STATUS
approved