OFFSET
1,1
COMMENTS
Column 6 of A252192
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..3..1..2..0..1..2..3....2..2..3..1..2..3..1..2....0..1..2..3..1..2..0..1
..1..1..1..1..1..1..1..1....3..0..0..0..0..0..0..0....0..3..3..0..0..3..0..3
..3..2..1..0..2..1..3..2....2..1..3..2..1..3..2..1....3..2..1..0..2..1..0..2
..2..0..1..2..3..1..2..0....1..2..0..1..2..3..1..2....0..1..2..0..1..2..3..1
..1..1..1..1..1..1..1..1....3..0..0..3..0..0..0..0....3..3..0..0..3..3..0..0
..3..2..1..3..2..1..0..0....2..1..3..2..1..3..2..1....0..2..1..3..2..1..0..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 15 2014
STATUS
approved