OFFSET
1,1
COMMENTS
Column 3 of A223387.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 19*a(n-1) - 72*a(n-2) + 34*a(n-3) + 44*a(n-4) for n>5.
Empirical g.f.: x*(1 - x)*(5 - 33*x + 21*x^2 + 22*x^3) / (1 - 19*x + 72*x^2 - 34*x^3 - 44*x^4). - Colin Barker, Aug 20 2018
EXAMPLE
Some solutions for n=3:
..0..1..2....0..1..0....0..1..1....0..0..0....0..1..2....0..1..1....0..1..1
..2..0..2....2..2..2....1..2..2....1..1..1....0..2..1....2..0..0....2..0..0
..2..0..1....1..0..1....0..1..0....2..2..0....2..0..2....1..2..1....2..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 19 2013
STATUS
approved