OFFSET
1,1
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 7*a(n-1) - 12*a(n-2) = A005061(n+2) for n>7.
Conjectures from Colin Barker, Sep 09 2018: (Start)
G.f.: x*(13 + 12*x + 60*x^2 + 12*x^3 - 504*x^4 - 1584*x^5 - 1728*x^6) / ((1 - 3*x)*(1 - 4*x)).
a(n) = 4^(2+n) - 3^(2+n) for n>5.
(End)
EXAMPLE
Some solutions for n=4:
..5....0...-5....3....4....1....3...-3...-6....2....2....1...-5....1....0....2
.-4....2....2...-3...-5....1....1....3....3...-1....3....1....3....4....3....1
..2....0...-1....5....5...-3...-5....1....1....4...-5....1....0...-6...-3...-1
..3...-2....2...-6...-2....0....3...-5....1...-5....4...-1...-3....6....3....0
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 16 2013
STATUS
approved