OFFSET
1,1
COMMENTS
Column 3 of A198715.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 19*a(n-1) - 45*a(n-2) + 27*a(n-3).
Empirical g.f.: x*(2 - 13*x + 16*x^2) / ((1 - x)*(1 - 18*x + 27*x^2)). - Colin Barker, Mar 02 2018
EXAMPLE
Some solutions with all values from 0 to 3 for n=4:
..0..1..2....0..1..2....0..1..0....0..1..2....0..1..0....0..1..2....0..1..0
..2..0..3....2..3..1....1..0..1....3..2..3....2..0..2....2..3..0....1..2..3
..0..1..0....0..1..2....0..2..3....2..3..0....0..3..1....0..2..1....3..0..1
..3..2..3....3..2..1....3..0..1....1..2..3....2..1..3....1..0..3....0..3..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 29 2011
STATUS
approved