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 A277364 #14 Jul 16 2025 17:06:43
%S A277364 1,0,1,1,8,16,122,365,2795,11051,86472,422005,3403127,19628064,
%T A277364 164029595,1084948961,9433737120,69998462014,635182667816,
%U A277364 5199414528808,49344452550230,439841775811967,4371727233798927,42000637216351225,437489737355466560,4493269587087402967
%N A277364 Number of ways to partition a set of n elements into at most n/2 disjoint subsets.
%H A277364 Indranil Ghosh, <a href="/A277364/b277364.txt">Table of n, a(n) for n = 0..400</a>
%F A277364 a(n) = Sum_{k=0..floor(n/2)} Stirling2(n,k).
%t A277364 Table[Sum[StirlingS2[n, k], {k, 0, n/2}], {n, 0, 25}]
%o A277364 (PARI) a(n) = sum(k=0, n\2, stirling(n, k, 2)); \\ _Michel Marcus_, Oct 11 2016
%Y A277364 Cf. A000110, A008277, A048993.
%K A277364 nonn
%O A277364 0,5
%A A277364 _Vladimir Reshetnikov_, Oct 10 2016