OFFSET
1,1
COMMENTS
Row 4 of A188236.
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.: x*(15 - 15*x + 7*x^2 - 15*x^3 + 19*x^4 - 7*x^5) / ((1 - x)^4*(1 + x + x^2)). - Colin Barker, Apr 27 2018
EXAMPLE
Some solutions for n=4:
.-5...-4...-6...-3...-2...-5...-4...-4...-4...-4...-1...-6...-3...-2...-5...-4
.-3....1...-6...-1...-2....0...-1...-1....0...-4....0...-3...-2...-1...-1...-3
..2....1....6....1....0....0....1...-1....0....4....0....3....2....0....3....2
..6....2....6....3....4....5....4....6....4....4....1....6....3....3....3....5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 24 2011
STATUS
approved