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A123991 G.f.: (1-x^2+x^4)/((1-x)^2*(1-x^2)^4*(1-x^3)^4). 1
1, 2, 6, 14, 29, 56, 107, 186, 320, 530, 851, 1332, 2051, 3074, 4544, 6602, 9444, 13322, 18579, 25564, 34827, 46954, 62692, 82954, 108889, 141732, 183169, 235042, 299584, 379434, 477763, 598036, 744628, 922348, 1136838, 1394608, 1703246, 2071068, 2508084 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

Poincaré series [or Poincare series] P(C_{3,2}; x).

REFERENCES

B. Broer, Hilbert series for modules of covariants, in Algebraic Groups and Their Generalizations..., Proc. Sympos. Pure Math., 56 (1994), Part I, 321-331.

Y. Teranishi, The ring of invariants of matrices, Nagoya Math. J., 104 (1986), 149-161.

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 0..9999

Dragomir Z. Djokovic, Poincaré series [or Poincare series] of some pure and mixed trace algebras of two generic matrices. See Table 3, lines 4 and 5, also Table 5, lines 1 and 2.

FORMULA

G.f.: (1+x^6)/((1-x)^2*(1-x^2)^3*(1-x^3)^4*(1-x^4)).

MATHEMATICA

CoefficientList[Series[(1-x^2+x^4)/((1-x)^2(1-x^2)^4(1-x^3)^4), {x, 0, 40}], x] (* Harvey P. Dale, Dec 20 2014 *)

CROSSREFS

Sequence in context: A214907 A169948 A192705 * A112511 A063452 A009299

Adjacent sequences:  A123988 A123989 A123990 * A123992 A123993 A123994

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 21 2006

STATUS

approved

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Last modified June 2 17:02 EDT 2020. Contains 334787 sequences. (Running on oeis4.)