OFFSET
1,1
COMMENTS
Column 6 of A204370.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 3*a(n-1) -6*a(n-4) +4*a(n-6) for n>9.
Empirical g.f.: x*(6121 - 14008*x - 10491*x^2 - 4766*x^3 + 31138*x^4 + 21146*x^5 - 14336*x^6 - 7620*x^7 - 200*x^8) / ((1 - x)*(1 - 2*x - 2*x^2)*(1 - 2*x^3)). - Colin Barker, Jun 07 2018
EXAMPLE
Some solutions for n=5:
..0..1..2..0..1..0..1..2....0..1..0..0..1..1..0..0....0..0..1..2..1..2..2..2
..0..1..2..0..1..0..1..2....0..1..0..0..1..1..0..0....0..0..1..2..1..2..2..1
..0..1..2..0..1..0..1..2....0..1..0..0..1..1..0..0....0..0..1..2..1..2..2..1
..0..1..2..0..1..0..1..2....0..1..0..0..1..1..0..0....0..0..1..2..1..2..2..1
..0..1..2..0..1..0..1..2....0..1..0..0..1..1..0..0....0..0..1..2..1..2..2..1
..0..1..2..0..1..0..1..2....0..0..0..0..1..1..0..0....0..0..1..2..1..2..2..1
..0..1..2..0..1..0..1..2....2..1..0..0..1..1..0..0....0..0..1..2..1..2..2..1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 14 2012
STATUS
approved