OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 6*a(n-3) + 4*a(n-5).
Empirical g.f.: x*(1 + 4*x + 6*x^2 + 4*x^3 + 4*x^4) / (1 - x - 6*x^3 - 4*x^5). - Colin Barker, Feb 22 2019
EXAMPLE
Some solutions for n=5:
..1..1. .1..0. .0..0. .0..1. .1..0. .0..1. .0..0. .1..1. .1..1. .0..0
..1..0. .1..1. .0..0. .1..1. .1..1. .1..1. .0..0. .1..0. .0..1. .0..0
..1..1. .0..0. .0..0. .0..0. .1..1. .0..0. .1..1. .1..1. .1..1. .1..0
..0..0. .1..0. .1..0. .0..1. .1..0. .0..0. .1..0. .1..1. .1..1. .1..1
..0..0. .1..1. .1..1. .1..1. .0..0. .0..0. .0..0. .1..0. .0..1. .0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 03 2017
STATUS
approved