OFFSET
1,2
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) - 17*a(n-3) + 19*a(n-5) - 16*a(n-6) + 8*a(n-7) for n>9.
Empirical g.f.: x^2*(1 - x)*(4 + 5*x - 21*x^2 - 5*x^3 - 9*x^4 + 2*x^5 - 2*x^6) / (1 - 6*x - 3*x^2 + 17*x^3 - 19*x^5 + 16*x^6 - 8*x^7). - Colin Barker, Feb 09 2019
EXAMPLE
Some solutions for n=4:
..0..0..1. .0..1..1. .0..1..1. .0..1..1. .0..1..0. .0..0..1. .0..0..0
..1..1..1. .0..0..0. .0..0..0. .0..0..0. .0..1..0. .1..1..1. .1..1..1
..1..1..1. .1..0..1. .0..1..1. .1..1..1. .1..0..1. .1..1..0. .0..0..0
..0..0..0. .1..0..1. .0..0..1. .0..0..0. .0..0..0. .0..0..0. .0..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 16 2016
STATUS
approved