OFFSET
1,1
COMMENTS
Column 1 of A209553.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-1) - 6*a(n-2) + 2*a(n-4).
Empirical g.f.: x*(7 - 15*x + 3*x^2 + 6*x^3) / ((1 - x)*(1 - 4*x + 2*x^2 + 2*x^3)). - Colin Barker, Jul 11 2018
EXAMPLE
Some solutions for n=4:
..0..1....0..1....3..2....3..0....2..3....0..2....0..1....1..3....1..2....0..1
..3..2....1..2....0..1....0..3....3..2....2..0....3..2....3..1....0..1....1..2
..0..1....2..1....1..2....1..2....2..3....0..2....2..1....1..3....1..2....0..3
..3..2....1..2....0..1....2..3....3..2....2..0....1..2....3..1....2..3....3..0
..2..3....0..1....1..0....1..2....2..3....0..2....2..1....1..3....3..2....2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 10 2012
STATUS
approved