A089596 G.f.: (1+2*x^3+3*x^6+x^8+6*x^9+2*x^11+9*x^12+x^14+10*x^15+x^16+9*x^18+2*x^19 +6*x^21 +x^22+3*x^24+2*x^27+x^30) / ((1-x^5)^2*(1-x^12)^2).

1, 0, 0, 2, 0, 2, 3, 0, 5, 6, 3, 8, 11, 8, 13, 18, 14, 22, 26, 22, 35, 38, 34, 48, 55, 52, 64, 74, 72, 88, 97, 94, 117, 126, 123, 148, 161, 160, 183, 200, 202, 228, 244, 246, 281, 298, 298, 336, 359, 362, 398, 424, 432, 472, 497, 506, 555, 582, 589, 642, 677, 686, 737, 776, 792

Offset

0,4

Comments

A_8 = SL_2(4) and acts on F_2[x_1, ..., x_4]. This is the Poincaré series [or Poincare series] (or Molien series) for the subgroup A_5 = SL_2(F_4). See A090492 for the other A_5.

References

A. Adem and R. J. Milgram, Cohomology of Finite Groups, Springer-Verlag, 2nd. ed., 2004; p. 113.

Links

Table of n, a(n) for n=0..64.

Mathematica

CoefficientList[Series[(1+2x^3+3x^6+x^8+6x^9+2x^11+9x^12+x^14+10x^15 +x^16 +9x^18+2x^19+6x^21+ x^22+3x^24+2x^27+x^30)/((1-x^5)^2(1-x^12)^2), {x, 0, 80}], x]  (* Harvey P. Dale, Apr 02 2011 *)

Crossrefs

Sequence in context: A262878 A317239 A360174 * A319876 A105805 A330368

Adjacent sequences: A089593 A089594 A089595 * A089597 A089598 A089599

Keyword

nonn

Author

N. J. A. Sloane, Dec 31 2003

Status

approved