OFFSET
1,1
COMMENTS
Column 3 of A195969.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-3) +2*a(n-4) +2*a(n-5) +4*a(n-6) -a(n-9) for n>11.
Empirical g.f.: x*(2 + 2*x + 5*x^2 + 3*x^3 + 6*x^4 + 7*x^5 - x^6 - 4*x^7 - 5*x^8 - x^9 - 2*x^10) / (1 - 2*x^3 - 2*x^4 - 2*x^5 - 4*x^6 + x^9). - Colin Barker, May 08 2018
EXAMPLE
All solutions for n=4:
..0..1..1....2..2..2....2..2..2....0..1..1....1..1..0....2..2..2....1..1..0
..1..2..2....2..0..2....2..0..2....2..2..2....2..2..1....2..1..2....2..2..2
..1..2..2....2..2..2....2..2..2....2..0..2....2..2..1....2..1..2....2..0..2
..0..1..1....1..1..0....0..1..1....2..2..2....1..1..0....2..2..2....2..2..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 25 2011
STATUS
approved