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 A326372 #8 Jul 02 2019 11:18:15
%S A326372 2,3,5,13,82,2647,1422565,229809982113,423295099074735261881
%N A326372 Number of intersecting antichains of (possibly empty) subsets of {1..n}.
%C A326372 A set system (set of sets) is an antichain if no edge is a subset of any other, and is intersecting if no two edges are disjoint.
%F A326372 a(n) = A001206(n + 1) + 1.
%e A326372 The a(0) = 2 through a(3) = 13 antichains:
%e A326372 {} {} {} {}
%e A326372 {{}} {{}} {{}} {{}}
%e A326372 {{1}} {{1}} {{1}}
%e A326372 {{2}} {{2}}
%e A326372 {{1,2}} {{3}}
%e A326372 {{1,2}}
%e A326372 {{1,3}}
%e A326372 {{2,3}}
%e A326372 {{1,2,3}}
%e A326372 {{1,2},{1,3}}
%e A326372 {{1,2},{2,3}}
%e A326372 {{1,3},{2,3}}
%e A326372 {{1,2},{1,3},{2,3}}
%Y A326372 The case without empty edges is A001206.
%Y A326372 The inverse binomial transform is the spanning case A305844.
%Y A326372 The unlabeled case is A306007.
%Y A326372 Maximal intersecting antichains are A326363.
%Y A326372 Intersecting set systems are A051185.
%Y A326372 Cf. A000372, A007363, A014466, A305843, A326361, A326362.
%K A326372 nonn,more
%O A326372 0,1
%A A326372 _Gus Wiseman_, Jul 01 2019