OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 13*a(n-2) - a(n-3) - 23*a(n-4) - 28*a(n-5) + 11*a(n-6) + 40*a(n-7) - 9*a(n-8) - 5*a(n-9) + 5*a(n-10).
Empirical g.f.: 2*x*(1 - x - 3*x^2 - 2*x^3 + 3*x^4 + 7*x^5 - x^6 - x^7 + x^8) / (1 - 2*x - 13*x^2 + x^3 + 23*x^4 + 28*x^5 - 11*x^6 - 40*x^7 + 9*x^8 + 5*x^9 - 5*x^10). - Colin Barker, Oct 26 2018
EXAMPLE
Some solutions for n=5:
..0..1..2....0..1..0....0..1..0....0..1..2....0..1..0....0..1..2....0..1..2
..0..1..2....0..1..0....0..1..0....0..1..2....0..1..0....0..1..2....0..1..2
..0..1..0....0..1..2....2..0..2....0..2..0....1..2..1....0..1..2....2..1..2
..2..1..0....0..1..2....2..0..2....0..2..0....1..2..1....0..1..2....2..1..2
..2..1..0....1..2..0....1..0..1....1..0..1....0..1..0....1..0..1....1..2..0
..2..1..0....1..2..0....1..0..1....1..0..1....0..1..0....1..0..1....1..2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 21 2014
STATUS
approved