OFFSET
0,4
COMMENTS
Poincaré series [or Poincare series] (or Molien series) for F_4[x_1, y_1]^{Z/3}.
REFERENCES
A. Adem and R. J. Milgram, Cohomology of Finite Groups, Springer-Verlag, 2nd. ed., 2004; p. 91.
LINKS
Harvey P. Dale, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (0,0,2,0,0,-1).
FORMULA
a(0)=1, a(1)=0, a(2)=1, a(3)=3, a(4)=0, a(5)=2, a(n)=2*a(n-3)-a(n-6). - Harvey P. Dale, May 20 2012
MATHEMATICA
CoefficientList[Series[(1+x^2+x^3)/(1-x^3)^2, {x, 0, 90}], x] (* or *) LinearRecurrence[{0, 0, 2, 0, 0, -1}, {1, 0, 1, 3, 0, 2}, 90] (* Harvey P. Dale, May 20 2012 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Dec 31 2003
STATUS
approved