OFFSET
1,1
COMMENTS
Column 2 of A220786.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..179
FORMULA
Empirical: a(n) = 5*a(n-1) + 6*a(n-2) - 4*a(n-3).
Empirical g.f.: x*(2 - x)*(1 + x) / (1 - 5*x - 6*x^2 + 4*x^3). - Colin Barker, Mar 13 2018
EXAMPLE
Some solutions for n=3:
..1..2....0..1....0..0....1..1....0..0....1..0....1..1....2..2....1..0....0..0
..0..1....0..2....1..1....1..1....1..1....3..2....1..2....2..2....2..1....0..0
..1..1....1..2....0..0....0..0....1..1....2..2....0..1....0..0....0..0....0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2012
STATUS
approved