OFFSET
1,1
COMMENTS
Column 3 of A218522.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..157
FORMULA
Empirical: a(n) = 18*a(n-1) - 19*a(n-2) - 96*a(n-3) - 112*a(n-4) - a(n-5) + 140*a(n-6) + 64*a(n-7).
Empirical g.f.: 2*x*(8 - x - 105*x^2 - 114*x^3 - 48*x^4 + 156*x^5 + 96*x^6) / (1 - 18*x + 19*x^2 + 96*x^3 + 112*x^4 + x^5 - 140*x^6 - 64*x^7). - Colin Barker, Jul 24 2018
EXAMPLE
Some solutions for n=3:
..0..0..1....2..0..3....3..2..2....2..2..3....0..0..0....0..0..1....1..1..1
..0..0..0....0..0..1....2..1..1....2..2..0....2..0..1....3..1..1....2..1..2
..1..0..1....2..0..0....2..1..3....0..0..0....3..0..0....1..1..3....1..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 31 2012
STATUS
approved