OFFSET
1,1
COMMENTS
Row 4 of A200057.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = 3*a(n-1) -3*a(n-2) +2*a(n-3) -3*a(n-4) +3*a(n-5) -a(n-6).
Empirical g.f.: 2*x*(2 + x + x^2)*(1 + 3*x + x^2) / ((1 - x)^4*(1 + x + x^2)). - Colin Barker, May 17 2018
EXAMPLE
Some solutions for n=6:
..2....6...-2....5....6...-2....2...-3....5....2....1....0....3....2....1....6
..5...-6...-3...-2...-4...-3...-4...-4...-5....0....3...-5...-3...-1...-4...-3
.-5....3....5....1....1....3....6....6....6....1...-3....5....1....0....5....0
.-2...-3....0...-4...-3....2...-4....1...-6...-3...-1....0...-1...-1...-2...-3
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 13 2011
STATUS
approved