OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 13*a(n-1) - 5*a(n-2) - 52*a(n-3) + 48*a(n-4).
Empirical g.f.: 2*x*(93 - 74*x - 368*x^2 + 384*x^3) / (1 - 13*x + 5*x^2 + 52*x^3 - 48*x^4). - Colin Barker, Nov 29 2018
EXAMPLE
Some solutions for n=3:
..0..2....3..0....0..3....2..1....2..1....0..1....0..2....0..0....2..1....0..2
..3..2....0..1....1..2....3..0....1..3....3..1....2..2....3..3....0..3....2..2
..0..3....2..1....1..2....2..0....0..1....3..0....0..2....2..0....1..1....0..3
..0..1....1..1....3..1....2..3....1..3....0..2....0..2....0..3....1..2....0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 03 2014
STATUS
approved