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 A343278 #13 Apr 20 2021 18:45:29
%S A343278 1,1,1,3,7,25,90,350,1701,6951,42525,179487,1323652,5715424,49329280,
%T A343278 216627840,2141764053,9528822303,106175395755,477297033785,
%U A343278 5917584964655,26826851689001,366282500870286,1672162773483930,24930204590758260,114485073343744260
%N A343278 a(n) = Stirling2(n, ceiling(n/2)).
%C A343278 Number of partitions of an n-set into ceiling(n/2) nonempty subsets.
%t A343278 Table[StirlingS2[n, Ceiling[n/2]], {n, 0, 25}] (* _Amiram Eldar_, Apr 20 2021 *)
%o A343278 (PARI) a(n) = stirling(n, ceil(n/2), 2); \\ _Michel Marcus_, Apr 20 2021
%Y A343278 Bisection gives A007820 (even part),
%Y A343278 Cf. A048993, A129506, A343279.
%K A343278 nonn
%O A343278 0,4
%A A343278 _Peter Luschny_, Apr 20 2021