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 A056937 #19 Jun 01 2025 22:53:04 %S A056937 1,980,211250,17792748,781429368,21238316210,398925639186, %T A056937 5585711269074,61555624183223,555895303974238,4242859829536322, %U A056937 28038281717424550,163544036697306396,855242362045150398 %N A056937 Number of antichains (or order ideals) in the poset 3*3*3*n or size of the distributive lattice J(3*3*3*n). %D A056937 Berman and Koehler, Cardinalities of finite distributive lattices, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), p. 103-124 %H A056937 J. Berman and P. Koehler, <a href="/A006356/a006356.pdf">Cardinalities of finite distributive lattices</a>, Mitteilungen aus dem Mathematischen Seminar Giessen, 121 (1976), 103-124. [Annotated scanned copy] %H A056937 <a href="/index/Pos#posets">Index entries for sequences related to posets</a> %Y A056937 Cf. A000372, A006360, A006361, A006362, A056932, A056933, A056934, A056935, A056936. %K A056937 nonn,easy %O A056937 0,2 %A A056937 _Mitch Harris_