OFFSET
1,1
COMMENTS
Column 2 of A206054.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 9*a(n-1) + a(n-2) - 24*a(n-3) + 15*a(n-4) - 6*a(n-5) + 4*a(n-6).
Empirical g.f.: 3*x*(85 + 5*x - 215*x^2 + 135*x^3 - 54*x^4 + 36*x^5) / (1 - 9*x - x^2 + 24*x^3 - 15*x^4 + 6*x^5 - 4*x^6). - Colin Barker, Jun 13 2018
EXAMPLE
Some solutions for n=4:
..1..2..1....0..2..0....2..0..0....0..2..2....0..1..2....2..1..2....1..1..1
..2..2..0....0..0..0....0..0..1....2..2..1....0..1..1....0..1..2....0..0..1
..0..0..0....2..0..1....0..1..1....2..0..1....0..1..0....0..1..1....2..0..0
..2..0..1....2..0..0....1..1..2....2..0..1....0..0..0....0..1..2....2..2..2
..2..0..0....2..2..0....2..2..2....2..0..1....1..0..1....0..1..1....1..1..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 03 2012
STATUS
approved