OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-1) + a(n-3) + a(n-6) - a(n-7) - a(n-9).
Empirical g.f.: x*(2 + 2*x - 5*x^4 + 3*x^5 - 10*x^6 - x^7 - 7*x^8) / ((1 - x)*(1 + x)*(1 - x + x^2)*(1 + x + x^2)*(1 - x - x^3)). - Colin Barker, Jan 09 2019
EXAMPLE
All solutions for n=4:
..0..0..0....1..2..1....0..0..0....2..1..1....2..3..2....1..1..2
..2..3..2....1..2..1....0..0..0....1..1..2....3..4..3....2..1..1
..3..4..3....1..2..1....0..0..0....1..1..2....2..3..2....2..1..1
..2..3..2....1..2..1....0..0..0....2..1..1....0..0..0....1..1..2
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2015
STATUS
approved