OFFSET
1,1
COMMENTS
Column 2 of A221225.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..22
FORMULA
Empirical: a(n) = 15*a(n-1) - 43*a(n-2) + 10*a(n-3).
Empirical g.f.: x*(3 - 10*x + 4*x^2) / (1 - 15*x + 43*x^2 - 10*x^3). - Colin Barker, Aug 04 2018
EXAMPLE
Some solutions for n=3:
..0..0....2..0....2..1....2..0....1..3....0..0....3..1....0..0....2..1....2..0
..4..0....2..1....0..0....2..0....0..0....1..2....1..1....5..1....0..1....0..2
..0..2....1..0....1..2....1..1....0..2....3..0....0..0....0..0....2..0....2..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 05 2013
STATUS
approved