OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 16*a(n-3) - 16*a(n-4) - 39*a(n-6) + 39*a(n-7) - 36*a(n-9) + 36*a(n-10).
Empirical g.f.: 2*x*(235 + 336*x + 630*x^2 - 2566*x^3 - 1620*x^4 - 2610*x^5 + 4323*x^6 - 864*x^7 - 2592*x^8 + 4788*x^9) / ((1 - x)*(1 - 4*x^3)*(1 - 12*x^3 - 9*x^6)). - Colin Barker, Nov 30 2018
EXAMPLE
Some solutions for n=4:
..2..0..1....1..2..3....0..3..0....2..1..0....2..3..1....1..2..3....2..0..1
..3..3..0....3..0..3....3..2..1....3..3..0....3..3..0....2..1..0....1..0..2
..1..0..2....2..1..0....0..1..2....1..2..3....1..0..2....0..0..3....0..3..3
..2..3..1....1..2..0....3..0..0....2..1..3....2..3..1....1..2..0....2..3..1
..3..0..0....0..3..3....3..2..1....3..0..0....3..3..0....2..1..3....1..0..2
..1..3..2....2..1..3....0..1..2....1..2..0....1..0..2....0..3..0....3..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 08 2014
STATUS
approved