OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + 6*a(n-3) - 6*a(n-4) - 10*a(n-6) + 10*a(n-7) + 3*a(n-9) - 3*a(n-10) for n>12.
Empirical g.f.: x*(129 - 60*x + 17*x^2 - 748*x^3 + 395*x^4 - 35*x^5 + 1208*x^6 - 715*x^7 - 51*x^8 - 367*x^9 + 219*x^10 + 24*x^11) / ((1 - x)*(1 - 3*x^3)*(1 - 3*x^3 + x^6)). - Colin Barker, Dec 05 2018
EXAMPLE
Some solutions for n=4:
..0..0..1..0..0..1..0....0..1..0..0..1..0..0....0..1..1..0..1..1..2
..1..0..0..1..0..0..2....1..1..2..1..1..2..1....1..0..1..1..0..1..1
..3..0..3..3..0..3..3....3..1..1..2..1..1..2....3..3..1..3..3..1..3
..0..0..1..0..0..1..0....0..1..0..0..1..0..0....0..1..1..0..1..1..0
..1..0..0..1..0..0..1....1..1..3..1..1..2..1....1..0..1..1..0..1..1
..3..0..3..3..0..3..3....3..1..1..3..1..1..2....2..2..1..2..2..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved
