OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 5*a(n-3) - 6*a(n-6) - a(n-9) + a(n-12) for n>15.
Empirical g.f.: x*(51 + 83*x + 133*x^2 - 135*x^3 - 196*x^4 - 315*x^5 + 8*x^6 - 66*x^7 - 106*x^8 + 15*x^9 + 65*x^10 + 103*x^11 - x^12 - 6*x^13 - 9*x^14) / ((1 - 3*x^3 + x^6)*(1 - 2*x^3 - x^6)). - Colin Barker, Dec 08 2018
EXAMPLE
Some solutions for n=4:
..0..1..2..0..1....0..0..0..0..0....0..0..0..0..0....0..1..2..0..3
..1..0..2..1..0....1..2..0..1..2....1..2..0..1..2....2..2..2..2..2
..2..2..2..2..2....2..1..0..2..1....2..1..0..2..1....3..0..2..1..0
..0..1..2..0..3....0..0..0..0..0....0..0..0..0..0....0..3..2..0..1
..1..0..2..3..0....1..2..0..1..3....3..2..0..1..3....2..2..2..2..2
..2..2..2..2..2....2..3..0..2..1....2..1..0..2..1....3..0..2..3..0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 26 2014
STATUS
approved