OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 16*a(n-1) - 60*a(n-2) + 116*a(n-3) - 104*a(n-4) + 48*a(n-5) - 11*a(n-6) + a(n-7).
Empirical g.f.: x*(196 - 844*x + 1752*x^2 - 1616*x^3 + 757*x^4 - 175*x^5 + 16*x^6) / (1 - 16*x + 60*x^2 - 116*x^3 + 104*x^4 - 48*x^5 + 11*x^6 - x^7). - Colin Barker, Nov 28 2018
EXAMPLE
Some solutions for n=3:
..3..0....3..3....3..3....2..2....1..2....2..0....3..0....1..0....2..2....2..0
..2..2....2..1....2..0....2..2....3..2....3..1....0..1....2..2....3..1....3..1
..2..0....2..2....1..0....2..3....3..3....2..3....1..1....2..3....3..2....2..2
..3..3....2..3....1..1....2..1....2..1....3..3....2..2....2..3....1..1....0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 01 2014
STATUS
approved