OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = -a(n-1) + 3*a(n-3) + 3*a(n-4) - 2*a(n-6) - 2*a(n-7) for n>9.
Empirical g.f.: x*(257 + 477*x + 444*x^2 - 290*x^3 - 886*x^4 - 720*x^5 - 232*x^6 + 144*x^7 + 16*x^8) / ((1 - x)*(1 + x)*(1 + x + x^2)*(1 - 2*x^3)). - Colin Barker, Dec 06 2018
EXAMPLE
Some solutions for n=4:
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..2
..0..2..0..0..3..0....1..0..1..1..0..1....1..1..2..1..1..2....0..3..3..0..3..3
..0..0..2..0..0..3....2..2..1..2..2..1....3..1..1..2..1..1....0..1..0..0..1..0
..0..1..1..0..1..1....0..1..1..0..1..1....0..1..0..0..1..0....0..0..1..0..0..1
..0..3..0..0..2..0....1..0..1..1..0..1....1..1..3..1..1..2....0..3..3..0..3..3
..0..0..3..0..0..2....2..2..1..2..2..1....3..1..1..3..1..1....0..2..0..0..1..0
..0..1..1..0..1..1....3..1..1..0..1..1....0..1..0..0..1..0....0..0..2..0..0..1
..0..3..0..0..3..0....1..3..1..1..0..1....1..1..3..1..1..3....0..3..3..0..3..3
..0..0..3..0..0..3....2..2..1..2..2..1....2..1..1..3..1..1....0..2..0..0..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved