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 A378072 #37 May 16 2025 14:36:42 %S A378072 1,2,10,132,4824,493600,142343254 %N A378072 Number of elements in the completion of the Bruhat order on B_n. %C A378072 Lascoux and Schützenberger have shown that the completion of type B Bruhat order is distributive, and have described its irreducible elements. It follows that a(n) is the number of antichains in the poset of irreducible elements of the Bruhat order on B_n. %C A378072 This sequence is a type B analog of A005130, since ASMs form a lattice isomorphic to the completion of type A Bruhat order. %H A378072 A. Lascoux and M.-P. Schützenberger, <a href="https://doi.org/10.37236/1285">Treillis et bases des groupes de Coxeter</a>, Electron. J. Combin. 3 (1996), #R27. %Y A378072 Cf. A005130 (ASMs), A005158 (centrally symmetric ASMs), A000165 (number of elements in B_n). %K A378072 nonn,more %O A378072 0,2 %A A378072 _Ludovic Schwob_, Nov 16 2024 %E A378072 a(6) by _Dmitry I. Ignatov_, May 16 2025