OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 8*a(n-1) + 26*a(n-2) - 166*a(n-3) + 96*a(n-4) + 198*a(n-5) - 81*a(n-6).
Empirical g.f.: 6*(1 - 7*x + 2*x^2 + 21*x^3 - 9*x^4) / ((1 + x)*(1 - 9*x)*(1 - 3*x + x^2)*(1 + 3*x - 9*x^2)). - Colin Barker, Oct 26 2018
EXAMPLE
Some solutions for n=5:
..0..1..0..2....0..1..0..1....0..1..1..0....0..1..2..0....0..1..2..1
..0..1..0..2....0..1..0..1....0..1..1..0....0..1..2..0....0..1..2..1
..1..0..0..2....0..1..2..1....0..1..2..1....1..0..1..2....2..1..0..1
..1..0..0..2....0..2..2..1....1..2..2..1....1..0..1..2....2..0..0..1
..0..1..1..0....0..2..0..1....1..2..2..1....1..0..2..0....1..0..2..1
..0..1..1..0....0..2..0..1....1..2..2..1....1..0..2..0....1..0..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 21 2014
STATUS
approved