OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 12*a(n-2) - 4*a(n-3) - 16*a(n-4).
Empirical g.f.: 8*x*(6 + 17*x - 14*x^2 - 28*x^3) / (1 - x - 12*x^2 + 4*x^3 + 16*x^4). - Colin Barker, Oct 11 2018
EXAMPLE
Some solutions for n=5:
..3..1....1..2....2..2....0..1....1..1....3..2....2..1....1..2....3..1....1..1
..2..2....1..0....1..3....0..2....2..0....1..2....3..1....1..3....2..1....2..3
..0..1....1..2....1..2....0..1....2..1....1..0....2..2....2..2....3..1....1..1
..2..1....0..0....0..2....0..2....0..1....2..2....3..1....0..1....3..2....2..3
..0..1....1..2....0..1....1..2....2..1....0..1....2..2....2..2....3..1....2..1
..2..2....1..3....2..1....0..0....3..3....2..2....1..0....1..0....2..2....3..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 14 2013
STATUS
approved