OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) - 2*a(n-2) + 4*a(n-3) + a(n-4) + 3*a(n-5) + 8*a(n-6) + a(n-7) - 3*a(n-8) - a(n-9) for n>10.
Empirical g.f.: x*(5 + x + 7*x^2 + 6*x^3 + 7*x^4 + 11*x^5 - 4*x^6 - 10*x^7 - 5*x^8 - x^9) / (1 - 3*x + 2*x^2 - 4*x^3 - x^4 - 3*x^5 - 8*x^6 - x^7 + 3*x^8 + x^9). - Colin Barker, Jan 31 2019
EXAMPLE
Some solutions for n=4:
..0..1..2. .0..0..0. .0..0..0. .0..1..0. .0..0..0. .0..0..1. .0..1..1
..2..0..1. .1..1..2. .1..1..1. .2..2..2. .1..1..1. .2..2..0. .2..2..0
..1..2..2. .2..0..1. .2..2..2. .0..1..1. .2..0..2. .0..1..1. .1..1..1
..0..1..0. .1..2..0. .1..1..0. .2..0..0. .1..1..0. .2..0..0. .0..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 17 2016
STATUS
approved