OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) - a(n-2) - a(n-3) - 4*a(n-4) - 8*a(n-5).
Empirical g.f.: x*(3 - 2*x - 5*x^2 - 12*x^3 - 8*x^4) / (1 - 4*x + x^2 + x^3 + 4*x^4 + 8*x^5). - Colin Barker, Feb 25 2019
EXAMPLE
Some solutions for n=7:
..0..1. .0..0. .1..1. .0..0. .1..0. .0..0. .1..1. .0..0. .0..1. .0..0
..0..0. .1..1. .1..0. .0..0. .1..1. .1..1. .1..0. .1..1. .0..0. .1..0
..1..0. .1..1. .1..1. .0..1. .0..0. .0..1. .0..0. .1..0. .1..1. .1..1
..0..0. .1..1. .1..0. .1..1. .0..0. .1..1. .1..1. .0..0. .1..0. .1..0
..0..0. .0..0. .0..1. .0..1. .0..0. .1..1. .0..1. .0..0. .1..0. .1..1
..0..0. .0..0. .1..1. .1..1. .0..0. .0..0. .1..0. .0..1. .1..1. .1..1
..1..0. .1..0. .1..1. .1..1. .1..0. .0..0. .1..1. .0..0. .0..0. .0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 24 2017
STATUS
approved