OFFSET
1,2
COMMENTS
Row 4 of A208970.
LINKS
R. H. Hardin, Table of n, a(n) for n = 1..210
FORMULA
Empirical: a(n) = 2*a(n-1) + a(n-2) - 4*a(n-3) + a(n-4) + 2*a(n-5) - a(n-6).
Conjectures from Colin Barker, Jul 07 2018: (Start)
G.f.: x*(1 + x - 3*x^2 + x^3 + 2*x^4 - x^5) / ((1 - x)^4*(1 + x)^2).
a(n) = (2*n^3 + 6*n^2 + 28*n + 48) / 48 for n even.
a(n) = (2*n^3 + 6*n^2 + 22*n + 18) / 48 for n odd.
(End)
EXAMPLE
All solutions for n=5:
-2 -1 -2 -2 -1 -1 -1 0 -2 -2 -1
0 -1 0 -1 0 0 1 0 -1 -2 -1
2 0 1 1 0 1 -1 0 2 2 1
0 2 1 2 1 0 1 0 1 2 1
CROSSREFS
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 03 2012
STATUS
approved