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 A266760 #13 Feb 18 2024 12:31:10
%S A266760 1,6,20,51,111,216,386,646,1026,1560,2287,3251,4500,6086,8066,10502,
%T A266760 13460,17011,21231,26200,32002,38726,46466,55320,65391,76787,89620,
%U A266760 104006,120066,137926,157716,179571,203631,230040,258946,290502,324866,362200,402671,446451,493716,544646,599426,658246,721300,788787,860911,937880,1019906
%N A266760 Growth series for affine Coxeter group (or affine Weyl group) D_5.
%D A266760 N. Bourbaki, Groupes et Algèbres de Lie, Chap. 4, 5 and 6, Hermann, Paris, 1968. See Chap. VI, Section 4, Problem 10b, page 231, W_a(t).
%D A266760 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See Table 3.1, page 59.
%H A266760 Ray Chandler, <a href="/A266760/b266760.txt">Table of n, a(n) for n = 0..1000</a>
%H A266760 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (4, -6, 4, -1, 0, 0, 1, -4, 6, -4, 1).
%F A266760 The growth series for the affine Coxeter group of type D_k (k >= 3) has g.f. = Product_i (1-x^{m_i+1})/((1-x)*(1-x^{m_i})) where the m_i are [1,3,5,...,2k-3,k-1].
%F A266760 Here (k=5) the G.f. is -(1+t)*(t^3+1)*(1+t+t^2+t^3+t^4+t^5+t^6+t^7) / (-1+t^7) / (-1+t)^4.
%Y A266760 The growth series for the affine Coxeter groups D_3 through D_12 are A005893 and A266759-A266767.
%K A266760 nonn
%O A266760 0,2
%A A266760 _N. J. A. Sloane_, Jan 10 2016