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 A161457 #14 Aug 13 2025 22:13:57
%S A161457 1,9,44,155,440,1068,2298,4489,8095,13640,21670,32683,47043,64889,
%T A161457 86054,110010,135853,162337,187959,211089,230131,243694,250749,250749,
%U A161457 243694,230131,211089,187959,162337,135853,110010,86054,64889,47043,32683,21670,13640,8095,4489,2298,1068,440,155,44,9,1
%N A161457 Number of reduced words of length n in the Weyl group A_9.
%C A161457 Computed with Magma using commands similar to those used to compute A161409.
%D A161457 N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche I.)
%D A161457 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
%F A161457 G.f. for A_m is the polynomial Product_{k=1..m} (1-x^(k+1))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A008302.
%t A161457 CoefficientList[Series[QFactorial[9+1,q],{q,0,9*(9+1)/2}],q] (* _Wouter Meeussen_, Jul 12 2014 *)
%Y A161457 Cf. A008302, A161409.
%K A161457 fini,nonn,full
%O A161457 0,2
%A A161457 _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009