OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-1) +8*a(n-2) -6*a(n-3).
Empirical g.f.: 3*x^2*(1 - x) / (1 - 5*x - 8*x^2 + 6*x^3). - Colin Barker, Feb 06 2019
EXAMPLE
Some solutions for n=4:
..0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1. .0..1
..2..1. .2..0. .2..2. .2..1. .2..0. .2..0. .2..1. .2..0. .2..1. .2..2
..0..1. .1..1. .1..2. .0..1. .1..0. .0..2. .0..2. .1..0. .1..2. .0..2
..0..2. .0..2. .0..1. .2..2. .2..0. .1..2. .1..2. .2..1. .0..0. .1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 31 2016
STATUS
approved