OFFSET
1,1
COMMENTS
Column 6 of A252305
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 15*a(n-3) -70*a(n-6) +120*a(n-9) -64*a(n-12) for n>21
EXAMPLE
Some solutions for n=4
..2..1..3..2..2..3..2..2....3..0..0..3..0..0..0..0....2..0..1..2..0..1..2..3
..3..2..2..3..2..2..3..2....0..2..1..3..2..1..3..2....3..3..0..3..0..0..0..3
..3..1..3..3..1..3..3..0....2..0..1..2..3..1..2..3....0..2..1..3..2..1..0..2
..2..2..3..2..2..3..2..2....3..0..0..0..0..0..0..0....2..0..1..2..3..1..2..0
..3..2..2..3..2..2..3..2....3..2..1..3..2..1..3..2....3..0..0..0..3..0..3..0
..3..1..3..3..1..3..3..1....3..3..1..2..3..1..2..3....3..2..1..0..2..1..0..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 16 2014
STATUS
approved