OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 4*a(n-2) + 5*a(n-3) + 2*a(n-4) - 2*a(n-5) - 3*a(n-6) - 2*a(n-7) + a(n-9).
Empirical g.f.: x*(5 + 9*x + 6*x^2 + x^3 - 5*x^4 - 5*x^5 - 2*x^6 + x^7 + x^8) / ((1 + x + x^2)*(1 - 3*x - 2*x^2 + 2*x^5 + x^6 - x^7)). - Colin Barker, Feb 23 2019
EXAMPLE
Some solutions for n=5:
..0..0..1. .0..0..1. .0..1..0. .0..0..1. .0..1..0. .1..0..0. .1..1..0
..1..0..0. .0..0..0. .0..0..0. .1..0..0. .0..0..0. .0..1..0. .1..0..0
..0..0..0. .0..0..1. .1..0..0. .0..0..1. .1..0..0. .0..0..0. .0..0..0
..1..0..0. .1..0..0. .0..0..1. .0..0..0. .0..0..0. .0..0..1. .1..0..0
..0..0..0. .0..0..1. .0..1..1. .1..0..0. .0..0..0. .0..0..0. .0..1..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 10 2017
STATUS
approved