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 A343279 #10 Apr 20 2021 18:45:33
%S A343279 1,0,1,1,7,15,90,301,1701,7770,42525,246730,1323652,9321312,49329280,
%T A343279 408741333,2141764053,20415995028,106175395755,1144614626805,
%U A343279 5917584964655,71187132291275,366282500870286,4864251308951100,24930204590758260,362262620784874680
%N A343279 a(n) = Stirling2(n, floor(n/2)).
%C A343279 Number of partitions of an n-set into floor(n/2) nonempty subsets.
%t A343279 Table[StirlingS2[n, Floor[n/2]], {n, 0, 25}] (* _Amiram Eldar_, Apr 20 2021 *)
%o A343279 (PARI) a(n) = stirling(n, n\2, 2); \\ _Michel Marcus_, Apr 20 2021
%Y A343279 Cf. A007820, A048993, A129506, A343278.
%K A343279 nonn
%O A343279 0,5
%A A343279 _Peter Luschny_, Apr 20 2021