OFFSET
1,1
COMMENTS
Column 4 of A252523
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 21*a(n-3) -62*a(n-6) +47*a(n-9) -5*a(n-12) for n>17
EXAMPLE
Some solutions for n=4
..3..0..2..3..0..2....3..2..3..3..2..0....3..0..2..3..0..2....3..2..3..3..2..0
..0..3..2..3..3..2....3..2..3..3..2..3....2..2..1..2..2..1....0..2..3..3..2..3
..2..2..1..2..2..1....2..1..2..2..1..2....0..3..2..3..3..2....2..1..2..2..1..2
..3..3..2..3..3..2....3..2..3..0..2..3....3..3..2..3..3..2....3..2..3..3..2..0
..3..3..2..3..3..2....0..2..3..3..2..0....2..2..1..2..2..1....3..2..3..0..2..3
..2..2..1..2..2..1....2..1..2..2..1..0....3..3..2..0..3..2....2..1..2..2..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 18 2014
STATUS
approved