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 A384959 #12 Jun 23 2025 21:42:47
%S A384959 4,36,4524,15166380,2010484649524,14206021962108887860
%N A384959 Number of chains in the Bruhat order of type A_n.
%C A384959 The number of chains in the Bruhat order of the Weyl group A_n (isomorphic to the symmetric group S_{n+1}).
%D A384959 A. Bjorner and F. Brenti, Combinatorics of Coxeter Groups, Springer, 2009, 27-64.
%H A384959 V. V. Deodhar, <a href="https://doi.org/10.1016/1385-7258(78)90059-8">On Bruhat ordering and weight-lattice ordering for a Weyl group</a>, Indagationes Mathematicae, vol. 81, 1 (1978), 423-435.
%H A384959 A. Postnikov and R. P. Stanley, <a href="https://doi.org/10.1007/s10801-008-0125-4">Chains in the Bruhat order</a>, J. Algebr. Comb., 29 (2009), 133-174.
%Y A384959 Cf. A061710 (maximal chains), A000142 (the order size), A005130 (the size of Dedekind-MacNeille completion), A384061 (number of antichains).
%K A384959 nonn,more
%O A384959 1,1
%A A384959 _Dmitry I. Ignatov_, Jun 13 2025