This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A266776 #15 Oct 21 2022 22:06:55
%S A266776 1,0,1,1,2,2,4,4,7,7,11,12,18,19,27,30,40,44,58,64,82,91,113,126,155,
%T A266776 171,207,230,274,303,358,395,462,509,589,649,746,818,934,1024,1161,
%U A266776 1269,1432,1562,1753,1909,2131,2317,2577,2794,3095,3352,3698,3997,4396,4743,5200,5601,6121,6584,7177,7705,8377,8983,9741,10429,11285,12065
%N A266776 Molien series for invariants of finite Coxeter group A_7.
%C A266776 The Molien series for the finite Coxeter group of type A_k (k >= 1) has g.f. = 1/Product_{i=2..k+1} (1 - x^i).
%C A266776 Note that this is the root system A_k, not the alternating group Alt_k.
%D A266776 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.
%H A266776 Ray Chandler, <a href="/A266776/b266776.txt">Table of n, a(n) for n = 0..1000</a>
%H A266776 <a href="/index/Rec#order_35">Index entries for linear recurrences with constant coefficients</a>, signature (0, 1, 1, 1, 0, 0, -1, -1, -2, -2, -1, 1, 2, 2, 3, 2, 1, -1, -2, -3, -2, -2, -1, 1, 2, 2, 1, 1, 0, 0, -1, -1, -1, 0, 1).
%H A266776 <a href="/index/Mo#Molien">Index entries for Molien series</a>
%F A266776 G.f.: 1/((1-t^2)*(1-t^3)*(1-t^4)*(1-t^5)*(1-t^6)*(1-t^7)*(1-t^8)).
%t A266776 CoefficientList[Series[1/Product[1-t^k, {k,2,8}], {t, 0, 40}], t] (* _G. C. Greubel_, Oct 24 2018 *)
%o A266776 (PARI) t='t+O('t^40); Vec(1/prod(k=2,8, 1-t^k)) \\ _G. C. Greubel_, Oct 24 2018
%o A266776 (Magma) m:=40; R<t>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(&*[1-t^k: k in [2..8]]))); // _G. C. Greubel_, Oct 24 2018
%Y A266776 Molien series for finite Coxeter groups A_1 through A_12 are A059841, A103221, A266755, A008667, A037145, A001996, and A266776-A266781.
%K A266776 nonn,easy
%O A266776 0,5
%A A266776 _N. J. A. Sloane_, Jan 11 2016