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 A161956 #9 Mar 17 2025 22:16:31
%S A161956 1,28,405,4032,31058,197288,1075697,5174180,22396787,88562288,
%T A161956 323686749,1103799420,3538931886,10735761372,30981056614,85436083852,
%U A161956 226032307036,575653531156,1415485760287,3369314791024,7781762472652,17474847498496,38225466707386,81586894793272
%N A161956 Number of reduced words of length n in the Weyl group B_28.
%C A161956 Computed with MAGMA using commands similar to those used to compute A161409.
%D A161956 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
%D A161956 N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)
%H A161956 Andrew Howroyd, <a href="/A161956/b161956.txt">Table of n, a(n) for n = 0..784</a>
%F A161956 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.
%Y A161956 Row n=28 of A128084.
%K A161956 nonn,fini,full
%O A161956 0,2
%A A161956 _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009