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 A161456 #9 Mar 19 2025 11:19:53
%S A161456 1,8,35,111,285,628,1230,2191,3606,5545,8031,11021,14395,17957,21450,
%T A161456 24584,27073,28675,29228,28675,27073,24584,21450,17957,14395,11021,
%U A161456 8031,5545,3606,2191,1230,628,285,111,35,8,1
%N A161456 Number of reduced words of length n in the Weyl group A_8.
%C A161456 Computed with MAGMA using commands similar to those used to compute A161409.
%D A161456 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
%D A161456 N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.)
%F A161456 G.f. for A_m is the polynomial Prod_{k=1..m}(1-x^(k+1))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A008302.
%Y A161456 Row n=9 of A008302.
%K A161456 nonn,fini,full
%O A161456 0,2
%A A161456 _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009