OFFSET
2,3
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..1000
Fumio Hazama, Spectra of graphs attached to the space of melodies, Discr. Math., 311 (2011), 2368-2383. See Table 2.1.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1,1,-1).
FORMULA
G.f.: -x^4*(-2+x) / ( (x-1)*(x^2-x+1)*(x^2+x-1) ). - R. J. Mathar, Nov 15 2011
a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) + a(n-4) - a(n-5), with a(2)=0, a(3)=0, a(4)=2, a(5)=5, a(6)=9. - Harvey P. Dale, Jul 04 2013
MATHEMATICA
CoefficientList[Series[-x^2*(-2+x)/((x-1)*(x^2-x+1)*(x^2+x-1)), {x, 0, 50}], x] (* Vincenzo Librandi, Jul 10 2012 *)
LinearRecurrence[{3, -3, 1, 1, -1}, {0, 0, 2, 5, 9}, 40] (* Harvey P. Dale, Jul 04 2013 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Nov 12 2011
STATUS
approved