OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 20*a(n-6) - 20*a(n-7) - 64*a(n-12) + 64*a(n-13).
Empirical g.f.: x*(333 + 180*x + 280*x^2 + 428*x^3 + 640*x^4 + 932*x^5 - 5340*x^6 - 960*x^7 - 1408*x^8 - 2048*x^9 - 2944*x^10 - 4160*x^11 + 15552*x^12) / ((1 - x)*(1 - 2*x^3)*(1 + 2*x^3)*(1 - 4*x^3)*(1 + 4*x^3)). - Colin Barker, Nov 08 2018
EXAMPLE
Some solutions for n=6:
..0....0....1....2....0....0....1....1....1....2....1....0....1....1....2....1
..1....2....1....0....1....0....0....1....0....0....2....0....1....0....2....2
..0....2....0....0....2....0....0....0....1....0....1....2....1....0....0....1
..2....1....2....2....1....1....0....2....2....0....0....1....2....1....2....0
..0....2....2....1....1....0....0....2....2....1....0....0....1....0....1....2
..1....1....2....1....1....1....1....2....0....1....0....1....0....0....1....2
..0....0....1....2....0....2....1....1....1....2....1....0....1....1....0....1
..1....0....1....2....1....2....2....1....0....0....0....2....1....2....0....2
..2....2....2....0....0....2....0....2....1....2....1....0....1....0....0....1
..2....1....0....0....1....1....2....2....0....2....2....1....0....1....2....0
..0....0....0....1....1....0....2....2....2....1....2....2....1....0....1....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 30 2014
STATUS
approved