OFFSET
1,1
COMMENTS
Column 2 of A232295
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 4*a(n-1) +4*a(n-2) +a(n-3).
Empirical: G.f.: -x*(3+3*x+x^2) / ( -1+4*x+4*x^2+x^3 ). - R. J. Mathar, Nov 27 2013
EXAMPLE
Some solutions for n=7
..2..2....2..1....2..2....2..2....2..2....2..2....1..2....1..2....1..2....1..2
..2..0....0..2....2..0....2..1....0..1....2..1....0..1....1..0....2..1....2..0
..1..2....2..0....1..2....1..2....2..1....2..1....2..1....2..2....1..2....1..2
..2..2....1..2....2..0....2..2....0..2....2..2....0..2....2..1....2..1....1..2
..1..2....2..1....1..2....2..2....0..1....2..1....1..0....0..0....1..2....1..1
..2..0....0..1....1..2....1..2....2..1....2..1....0..1....1..2....2..2....2..1
..1..2....2..2....2..1....1..2....2..2....0..2....2..2....2..2....2..1....2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 22 2013
STATUS
approved