OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 10*a(n-1) + 14*a(n-2) - 6*a(n-3) - a(n-4).
Empirical g.f.: x*(37 + 51*x - 17*x^2 - 3*x^3) / (1 - 10*x - 14*x^2 + 6*x^3 + x^4). - Colin Barker, Oct 03 2018
EXAMPLE
Some solutions for n=4:
..0..0..2....0..0..0....2..2..2....0..0..0....0..0..1....2..2..0....0..0..2
..0..2..1....0..0..2....0..0..0....1..2..1....1..2..2....0..0..1....0..2..2
..2..1..1....1..2..0....0..0..0....2..1..1....2..1..0....1..2..2....2..2..1
..1..2..1....2..0..0....1..2..2....1..0..0....0..0..2....0..0..1....0..0..1
..2..0..0....0..2..2....2..2..2....0..2..2....0..2..2....1..1..1....0..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 21 2013
STATUS
approved