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Molien series for alternating group Alt_8 (or A_8).
3

%I #21 Sep 08 2022 08:44:36

%S 1,1,2,3,5,7,11,15,22,29,40,52,70,89,116,146,186,230,288,352,434,525,

%T 638,764,919,1090,1297,1527,1802,2105,2464,2860,3324,3835,4428,5081,

%U 5834,6659,7604,8640,9819,11107,12566,14158,15951,17904,20093,22474,25133

%N Molien series for alternating group Alt_8 (or A_8).

%D D. J. Benson, Polynomial Invariants of Finite Groups, Cambridge, 1993, p. 105.

%H G. C. Greubel, <a href="/A008631/b008631.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Mo#Molien">Index entries for Molien series</a>

%H <a href="/index/Rec#order_32">Index entries for linear recurrences with constant coefficients</a>, signature (1,1,0,1,-2,-1,-1,-1,1,1,2,3,0,-1,-1,-4,-1,-1,0,3,2,1,1,-1,-1,-1,-2,1,0,1,1,-1).

%F G.f.: (1+x^28)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)*(1-x^5)*(1-x^6)*(1-x^7)*(1-x^8)).

%p seq(coeff(series( (1+x^28)/mul((1-x^j), j=1..8)), x, n+1), x, n), n = 0..50); # _G. C. Greubel_, Feb 02 2020

%t CoefficientList[Series[(1+x^28)/Product[(1-x^j), {j,1,8}], {x,0,50}], x] (* _G. C. Greubel_, Feb 02 2020 *)

%t LinearRecurrence[{1,1,0,1,-2,-1,-1,-1,1,1,2,3,0,-1,-1,-4,-1,-1,0,3,2,1,1,-1,-1,-1,-2,1,0,1,1,-1},{1,1,2,3,5,7,11,15,22,29,40,52,70,89,116,146,186,230,288,352,434,525,638,764,919,1090,1297,1527,1802,2105,2464,2860},70] (* _Harvey P. Dale_, May 12 2022 *)

%o (PARI) Vec( (1+x^28)/prod(j=1,8, 1-x^j) +O('x^50) ) \\ _G. C. Greubel_, Feb 02 2020

%o (Magma) R<x>:=PowerSeriesRing(Integers(), 50); Coefficients(R!( (1+x^28)/(&*[1-x^j: j in [1..8]]) )); // _G. C. Greubel_, Feb 02 2020

%o (Sage)

%o def A008631_list(prec):

%o P.<x> = PowerSeriesRing(ZZ, prec)

%o return P( (1+x^28)/product(1-x^j for j in (1..8)) ).list()

%o A008631_list(70) # _G. C. Greubel_, Feb 02 2020

%Y Different from A008637.

%K nonn,easy

%O 0,3

%A _N. J. A. Sloane_