OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-2) + a(n-3) - a(n-4) - 2*a(n-5) - 2*a(n-6) - a(n-7) + a(n-8) + a(n-9).
Empirical g.f.: x*(71 + 55*x + 9*x^2 - 54*x^3 - 73*x^4 - 57*x^5 - 15*x^6 + 36*x^7 + 27*x^8) / ((1 - x)*(1 - x - 3*x^2 - 4*x^3 - 3*x^4 - x^5 + x^6 + 2*x^7 + x^8)). - Colin Barker, Nov 05 2018
EXAMPLE
Some solutions for n=8:
..0....1....1....1....2....1....0....0....1....1....2....1....0....0....1....2
..1....1....2....1....0....2....2....1....0....2....0....0....0....1....1....0
..2....2....0....2....1....0....2....0....2....2....0....1....2....1....0....0
..0....1....0....0....1....1....0....2....0....1....2....2....0....0....1....1
..1....2....1....1....1....0....2....1....0....0....2....1....1....2....1....2
..0....1....1....0....1....1....2....0....1....1....0....0....0....2....1....1
..2....2....1....2....2....1....1....0....1....2....2....1....1....1....2....0
..2....0....1....2....1....0....0....1....0....2....0....0....2....0....1....2
..0....1....0....0....2....0....1....1....0....0....2....2....0....2....2....0
..0....1....1....1....0....2....1....2....2....2....2....1....2....0....1....0
..2....2....1....1....0....2....2....1....2....1....1....0....0....0....2....2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 08 2014
STATUS
approved