[go: up one dir, main page]

login
A008582
Molien series for Weyl group E_8.
2
1, 1, 1, 1, 2, 2, 3, 4, 5, 6, 8, 9, 12, 14, 17, 20, 25, 28, 34, 40, 47, 54, 64, 72, 85, 97, 111, 126, 146, 163, 187, 211, 238, 266, 302, 335, 378, 421, 469, 520, 582, 640, 712, 786, 868, 954, 1055, 1153, 1270, 1391, 1523, 1662, 1822, 1979, 2162, 2352, 2558, 2774, 3018, 3262
OFFSET
0,5
REFERENCES
Coxeter and Moser, Generators and Relations for Discrete Groups, Table 10.
L. Smith, Polynomial Invariants of Finite Groups, Peters, 1995, p. 199 (No. 37).
FORMULA
G.f.: 1/((1-x^2)*(1-x^8)*(1-x^12)*(1-x^14)*(1-x^18)*(1-x^20)*(1-x^24)*(1-x^30)).
a(n) ~ 1/13716864000*n^7 (for the sequence without interleaved zeros). - Ralf Stephan, Apr 29 2014
MAPLE
seq(coeff(series( mul(1/((1-x^(3*j+6))*(1-x^(3*j+1))), j=0..3), x, n+1), x, n), n = 0..60); # G. C. Greubel, Feb 02 2020
MATHEMATICA
Select[CoefficientList[Series[1/((1-x^2)(1-x^8)(1-x^12)(1-x^14)(1-x^18) (1-x^20)(1-x^24)(1-x^30)), {x, 0, 180}], x], #!=0&] (* Harvey P. Dale, Jun 09 2011 *)
CoefficientList[Series[Product[1/((1-x^(3*j+6))*(1-x^(3*j+1))), {j, 0, 3}], {x, 0, 60}], x] (* G. C. Greubel, Feb 02 2020 *)
PROG
(Magma) MolienSeries(CoxeterGroup("E8")); // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006
(PARI) Vec( prod(j=0, 3, 1/((1-x^(3*j+6))*(1-x^(3*j+1)))) +O('x^60) ) \\ G. C. Greubel, Feb 02 2020
(Sage)
def A008582_list(prec):
P.<x> = PowerSeriesRing(ZZ, prec)
return P( product(1/((1-x^(3*j+6))*(1-x^(3*j+1))) for j in (0..3)) ).list()
A008582_list(60) # G. C. Greubel, Feb 02 2020
CROSSREFS
Sequence in context: A319069 A029013 A114096 * A069911 A185225 A027196
KEYWORD
nonn,easy,nice
STATUS
approved