OFFSET
1,3
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) + 7*a(n-2) - 26*a(n-3) + 5*a(n-4) + 14*a(n-5).
Empirical g.f.: x*(1 - 3*x - 4*x^2 + 8*x^3) / ((1 - x - x^2)*(1 - 3*x - 9*x^2 + 14*x^3)).
EXAMPLE
Some solutions for n=5:
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
..0..2....1..2....2..0....2..1....2..1....1..0....2..0....2..1....2..0....2..0
..0..2....1..2....2..0....2..0....2..1....1..0....2..0....2..1....2..0....2..0
..2..0....1..3....3..0....2..0....1..3....1..0....1..0....3..1....0..1....3..2
..2..0....1..3....3..0....2..0....1..3....1..0....1..0....3..1....0..1....3..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 11 2014
STATUS
approved