OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 6*a(n-1) + 9*a(n-2) - 67*a(n-3) + 26*a(n-4) + 81*a(n-5) - 48*a(n-6) + 2*a(n-7).
Empirical g.f.: 2*x*(45 - 3*x - 505*x^2 + 312*x^3 + 619*x^4 - 405*x^5 + 17*x^6) / (1 - 6*x - 9*x^2 + 67*x^3 - 26*x^4 - 81*x^5 + 48*x^6 - 2*x^7). - Colin Barker, Oct 11 2018
EXAMPLE
Some solutions for n=5:
..0..1..1....0..1..0....1..0..1....1..1..1....1..2..1....1..2..1....1..1..1
..0..0..1....0..1..1....1..0..0....2..1..0....2..2..1....1..1..1....2..2..2
..1..1..1....1..1..2....1..0..1....2..1..1....2..1..1....0..1..0....1..1..1
..2..2..1....2..1..1....1..0..0....2..2..2....2..2..1....1..1..1....0..1..2
..1..2..1....2..1..0....1..1..0....1..2..1....1..2..1....2..2..2....1..1..1
..1..2..2....1..1..0....2..1..0....1..1..1....2..2..2....2..1..1....2..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 14 2013
STATUS
approved