OFFSET
1,1
COMMENTS
Column 2 of A295531.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + 5*a(n-3) - a(n-5) - a(n-6).
Empirical g.f.: x*(2 + 6*x + 5*x^2 - x^3 - 2*x^4 - x^5) / (1 - 2*x - 2*x^2 - 5*x^3 + x^5 + x^6). - Colin Barker, Feb 21 2018
EXAMPLE
Some solutions for n=5:
..1..1. .1..1. .1..1. .1..1. .1..0. .0..0. .0..0. .0..0. .0..1. .1..1
..1..0. .1..0. .1..1. .0..0. .1..0. .1..1. .1..1. .1..1. .0..1. .0..1
..1..1. .0..0. .0..0. .1..1. .1..0. .1..0. .0..0. .0..0. .0..0. .0..1
..0..1. .0..1. .1..0. .0..1. .1..1. .1..0. .1..1. .1..1. .1..0. .0..0
..0..1. .1..1. .1..1. .0..1. .0..0. .0..0. .1..0. .1..1. .1..1. .1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2017
STATUS
approved