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 A161991 #5 Jul 19 2015 10:23:32
%S A161991 1,34,594,7106,65449,494768,3195983,18134478,92219577,426746308,
%T A161991 1818523916,7204803796,26747139312,93651006988,310966484313,
%U A161991 983825011398,2977708459669,8652371731716,24211251121429,65420187465158
%N A161991 Number of reduced words of length n in the Weyl group B_34.
%C A161991 Computed with MAGMA using commands similar to those used to compute A161409.
%D A161991 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
%D A161991 N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)
%F A161991 G.f. for B_m is the polynomial Prod_{k=1..m}(1-x^(2k))/(1-x). Only finitely many terms are nonzero. This is a row of the triangle in A128084.
%K A161991 nonn
%O A161991 0,2
%A A161991 _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009