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 A161879 #10 Mar 17 2025 18:32:12
%S A161879 1,19,189,1311,7124,32300,127091,445721,1420364,4172476,11426240,
%T A161879 29429784,71808030,166970290,371826581,796341623,1646167391,
%U A161879 3294638285,6401307860,12102626404,22312161586,40184022430,70815181390,122291804610,207223417349,344959019207,564743768579
%N A161879 Number of reduced words of length n in the Weyl group B_19.
%C A161879 Computed with MAGMA using commands similar to those used to compute A161409.
%D A161879 J. E. Humphreys, Reflection Groups and Coxeter Groups, Cambridge, 1990. See under Poincaré polynomial.
%D A161879 N. Bourbaki, Groupes et alg. de Lie, Chap. 4, 5, 6. (The group is defined in Planche II.)
%H A161879 Andrew Howroyd, <a href="/A161879/b161879.txt">Table of n, a(n) for n = 0..361</a>
%F A161879 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 A161879 Row n=19 of A128084.
%K A161879 nonn,fini,full
%O A161879 0,2
%A A161879 _John Cannon_ and _N. J. A. Sloane_, Nov 30 2009