OFFSET
1,1
COMMENTS
Row 3 of A199909.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 2*a(n-1) -a(n-2) +a(n-3) -2*a(n-4) +a(n-5).
Empirical g.f.: 6*x*(1 + x^2) / ((1 - x)^3*(1 + x + x^2)). - Colin Barker, May 17 2018
EXAMPLE
Some solutions for n=6:
..0...-1....4....6...-1....4...-3...-6....6...-2....2....3...-5....6....2...-2
.-5....1...-6...-2....0...-1....1....1...-4....5...-2...-2....3...-5...-5....2
..5....0....2...-4....1...-3....2....5...-2...-3....0...-1....2...-1....3....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 11 2011
STATUS
approved