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 A327436 #8 Sep 11 2019 20:22:42
%S A327436 0,0,1,1,4,29
%N A327436 Number of connected, unlabeled antichains of nonempty subsets of {1..n} covering n vertices with at least one cut-vertex (vertex-connectivity 1).
%F A327436 a(n > 2) = A261006(n) - A305028(n).
%e A327436 Non-isomorphic representatives of the a(2) = 1 through a(5) = 29 antichains:
%e A327436 {12} {12}{13} {12}{134} {12}{1345}
%e A327436 {12}{13}{14} {123}{145}
%e A327436 {12}{13}{24} {12}{13}{145}
%e A327436 {12}{13}{14}{23} {12}{13}{245}
%e A327436 {13}{24}{125}
%e A327436 {13}{124}{125}
%e A327436 {14}{123}{235}
%e A327436 {12}{13}{14}{15}
%e A327436 {12}{13}{14}{25}
%e A327436 {12}{13}{24}{35}
%e A327436 {12}{13}{14}{235}
%e A327436 {12}{13}{23}{145}
%e A327436 {12}{13}{45}{234}
%e A327436 {12}{14}{23}{135}
%e A327436 {12}{15}{134}{234}
%e A327436 {15}{23}{124}{134}
%e A327436 {15}{123}{124}{134}
%e A327436 {15}{123}{124}{234}
%e A327436 {12}{13}{14}{15}{23}
%e A327436 {12}{13}{14}{23}{25}
%e A327436 {12}{13}{14}{23}{45}
%e A327436 {12}{13}{15}{24}{34}
%e A327436 {12}{13}{14}{15}{234}
%e A327436 {12}{13}{14}{25}{234}
%e A327436 {12}{13}{14}{15}{23}{24}
%e A327436 {12}{13}{14}{15}{23}{45}
%e A327436 {12}{13}{14}{23}{24}{35}
%e A327436 {15}{123}{124}{134}{234}
%e A327436 {12}{13}{14}{15}{23}{24}{34}
%Y A327436 Column k = 1 of A327359.
%Y A327436 The labeled version is A327356.
%Y A327436 Cf. A006602, A014466, A048143, A261005, A326704, A326786, A327112, A327114, A327426, A327334, A327336, A327350, A327351, A327358.
%K A327436 nonn
%O A327436 0,5
%A A327436 _Gus Wiseman_, Sep 11 2019