OFFSET
1,2
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) + 33*a(n-2) - 68*a(n-3).
Empirical g.f.: 32*x^2*(1 - 4*x) / (1 - 8*x - 33*x^2 + 68*x^3). - Colin Barker, Sep 25 2018
EXAMPLE
Some solutions for n=4:
..0..1..2..3....0..3..2..3....0..3..0..1....0..3..2..3....0..3..2..1
..0..3..0..3....2..1..0..3....2..1..2..3....0..1..0..3....0..1..0..1
..2..3..2..1....0..1..2..3....2..3..0..1....0..1..2..1....2..3..0..3
..0..1..0..3....2..3..0..3....0..1..2..1....2..3..0..3....0..1..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 03 2013
STATUS
approved