OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 3*a(n-3) - 3*a(n-4) - 4*a(n-5) + 4*a(n-6) - 4*a(n-7) for n>9.
Empirical g.f.: x*(4 + 9*x - 10*x^2 - 26*x^4 + 12*x^5 + 12*x^6 - 24*x^7 + 16*x^8) / (1 - 2*x - 3*x^3 + 3*x^4 + 4*x^5 - 4*x^6 + 4*x^7). - Colin Barker, Feb 19 2019
EXAMPLE
Some solutions for n=4:
..0..1..1. .0..1..0. .0..1..1. .0..1..1. .0..1..1. .0..1..1. .0..1..0
..0..1..0. .1..1..0. .0..1..0. .0..0..1. .0..1..0. .0..1..0. .0..1..0
..0..1..1. .0..0..1. .0..1..0. .1..0..1. .0..1..0. .1..1..0. .1..1..0
..1..0..0. .1..0..1. .0..1..0. .0..0..1. .1..0..1. .1..0..0. .1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 22 2017
STATUS
approved