OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 11*a(n-1) - 9*a(n-2) - 15*a(n-3) + 20*a(n-4) - 6*a(n-5) for n>6.
Empirical g.f.: 2*x*(4 - 11*x - 3*x^2 + 17*x^3 - 9*x^4 + x^5) / ((1 - x)*(1 - 10*x - x^2 + 14*x^3 - 6*x^4)). - Colin Barker, Feb 02 2019
EXAMPLE
Some solutions for n=4:
..0..1..2..0. .0..0..1..2. .0..1..0..1. .0..1..0..2. .0..1..2..1
..1..2..1..2. .2..1..0..1. .1..0..1..0. .1..0..1..0. .1..2..1..2
..0..1..2..0. .1..2..1..2. .0..2..0..1. .0..1..0..2. .2..1..0..1
..1..2..0..2. .2..1..2..1. .2..0..1..2. .1..0..1..0. .1..2..1..2
..0..1..2..0. .1..0..1..2. .1..2..0..1. .0..2..0..2. .2..1..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 20 2016
STATUS
approved