OFFSET
1,1
COMMENTS
Column 3 of A200886.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) -6*a(n-2) +10*a(n-3) -5*a(n-4) +6*a(n-5) -a(n-6) +a(n-7).
Empirical g.f.: x*(50 - 56*x + 146*x^2 - 56*x^3 + 93*x^4 - 12*x^5 + 16*x^6) / (1 - 4*x + 6*x^2 - 10*x^3 + 5*x^4 - 6*x^5 + x^6 - x^7). - Colin Barker, Oct 16 2017
EXAMPLE
Some solutions for n=3
..2....2....2....3....0....3....1....1....3....3....1....3....0....1....3....1
..0....2....1....2....0....3....1....2....2....3....0....3....1....1....1....2
..2....1....0....0....2....3....0....2....1....1....1....1....3....0....3....3
..2....2....0....1....3....3....2....0....2....1....2....0....3....0....3....3
..0....2....2....2....3....2....3....3....3....2....3....3....1....3....3....3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 23 2011
STATUS
approved