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 A368512 #7 Dec 28 2023 10:57:59
%S A368512 1,0,2,6,66,450,4550,45570,543130,7044450,102177222,1621316466,
%T A368512 28089336198,526810157874,10641259374174,230281144233426,
%U A368512 5315651069181882,130370668142722722,3385534486308684710,92801581965119911026,2677687786557636155446,81124824677426691365490
%N A368512 Number of ordered partitions of an n-set into blocks of size <= n/2.
%F A368512 a(n) = n! * [x^n] 1 / (1 - Sum_{1 <= j <= n/2} x^j / j!).
%F A368512 a(n) ~ sqrt(Pi/2) * n^(n + 1/2) / (exp(n) * log(2)^(n+1)). - _Vaclav Kotesovec_, Dec 28 2023
%t A368512 Table[n! SeriesCoefficient[1/(1 - Sum[x^j/j!, {j, 1, Floor[n/2]}]), {x, 0, n}], {n, 0, 21}]
%Y A368512 Cf. A000670, A368503, A368511.
%K A368512 nonn
%O A368512 0,3
%A A368512 _Ilya Gutkovskiy_, Dec 28 2023