OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) - 3*a(n-3) + a(n-4) + 4*a(n-5) - 3*a(n-6) + a(n-7) - 2*a(n-8) + a(n-9) for n>10.
Empirical g.f.: x*(2 + 5*x - 4*x^2 - 4*x^3 + 10*x^4 + 3*x^5 - 14*x^6 + 4*x^7 - 2*x^8 + 2*x^9) / (1 - 2*x - x^2 + 3*x^3 - x^4 - 4*x^5 + 3*x^6 - x^7 + 2*x^8 - x^9). - Colin Barker, Feb 04 2019
EXAMPLE
Some solutions for n=4:
..0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..1. .0..1. .0..0. .0..0
..0..1. .0..2. .1..2. .0..0. .2..2. .1..0. .2..0. .2..2. .1..0. .1..1
..2..2. .1..2. .1..1. .2..2. .1..2. .2..1. .1..2. .1..2. .2..1. .2..1
..1..2. .1..1. .2..0. .1..2. .0..0. .2..2. .0..1. .1..0. .0..2. .2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 26 2016
STATUS
approved