OFFSET
1,3
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 16*a(n-3) - 13*a(n-4) - 10*a(n-5) - 13*a(n-6) - 8*a(n-7) - 3*a(n-8) - 2*a(n-9) - a(n-10).
Empirical g.f.: 2*x^3*(1 - x - x^2)*(1 + x + x^2) / (1 - 3*x - 3*x^2 - x^3 - x^4 - x^5)^2. - Colin Barker, Feb 21 2019
EXAMPLE
Some solutions for n=4:
..0..1. .0..1. .1..1. .1..0. .1..1. .0..0. .0..1. .1..1. .1..1. .0..0
..1..1. .1..1. .1..1. .1..1. .1..1. .0..1. .0..1. .1..1. .1..1. .1..1
..1..1. .1..1. .1..0. .1..1. .1..0. .1..1. .1..1. .1..0. .1..0. .1..1
..0..0. .0..1. .1..1. .1..0. .0..1. .1..1. .1..1. .0..0. .1..0. .1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 08 2017
STATUS
approved