OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 16*a(n-1) - 86*a(n-2) + 156*a(n-3) + 48*a(n-4) - 256*a(n-5) - 64*a(n-6).
Empirical g.f.: 4*x*(22 - 225*x + 600*x^2 + 16*x^3 - 1056*x^4 - 256*x^5) / ((1 - 8*x + 14*x^2 + 4*x^3)*(1 - 8*x + 8*x^2 + 16*x^3)). - Colin Barker, Oct 20 2018
EXAMPLE
Some solutions for n=5:
..0..2....3..2....3..1....3..2....2..3....2..1....1..2....2..1....1..3....0..3
..3..1....2..1....2..2....2..1....2..1....2..3....3..2....1..2....2..2....2..1
..2..2....0..1....0..0....3..0....2..1....1..2....2..3....2..3....1..1....3..2
..1..3....1..2....3..3....2..1....2..1....1..0....1..0....1..2....2..2....2..3
..2..0....0..1....2..2....1..2....2..1....2..3....1..2....1..2....1..3....1..2
..1..1....1..0....1..3....1..2....2..1....1..0....3..2....0..1....2..2....2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 18 2014
STATUS
approved