OFFSET
1,1
COMMENTS
Row 4 of A199530.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..200
FORMULA
Empirical: a(n) = (16/3)*n^3 + 8*n^2 - (4/3)*n.
Conjectures from Colin Barker, May 15 2018: (Start)
G.f.: 4*x*(3 + 6*x - x^2) / (1 - x)^4.
a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>4.
(End)
EXAMPLE
Some solutions for n=5:
.-4...-4....4....0...-5....5....2....0...-1...-3....2....1....4...-1....4...-1
..4....5...-4....2....3...-2...-2...-2....0...-2...-2...-3...-1....2...-2....5
..3....1...-2...-5...-3...-1....1....1...-2....2....3....1....0....4....1....1
.-3...-2....2....3....5...-2...-1....1....3....3...-3....1...-3...-5...-3...-5
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 07 2011
STATUS
approved