OFFSET
1,1
COMMENTS
Column 4 of A229694
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 27*a(n-1) -243*a(n-2) +729*a(n-3) for n>4.
Empirical: g.f. 3*x-x^2*(245-1538*x+3213*x^2) / (9*x-1)^3. - R. J. Mathar, Sep 29 2013
EXAMPLE
Some solutions for n=3
..0..0..1..0....0..1..0..2....0..1..2..0....0..1..2..1....0..1..0..2
..1..0..1..2....2..1..0..0....0..1..0..2....0..2..0..2....2..1..0..1
..1..0..0..2....2..0..1..2....0..1..2..1....0..1..1..2....2..0..0..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 27 2013
STATUS
approved