OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = a(n-2) + 2*a(n-3) - 2*a(n-5) for n>8.
Empirical g.f.: x*(45 + 46*x + 5*x^2 - 73*x^3 - 73*x^4 + 18*x^5 + 4*x^6 + 2*x^7) / ((1 - x)*(1 + x)*(1 - 2*x^3)). - Colin Barker, Dec 05 2018
EXAMPLE
Some solutions for n=4:
..0..1..0..0..2..0....0..0..1..0..0..2....0..1..1..0..1..1....0..0..1..1..2..2
..0..0..1..0..0..2....1..3..3..0..3..3....0..2..0..0..2..0....1..2..2..3..3..0
..0..3..3..0..3..3....2..2..0..0..1..0....0..0..2..0..0..2....3..3..0..0..1..1
..0..1..0..0..1..0....0..0..1..0..0..1....0..3..3..0..3..3....0..1..1..2..2..3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 20 2014
STATUS
approved