cp's OEIS Frontend

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.

A098407 Number of different hierarchical orderings that can be formed from n unlabeled elements with no repetition of subhierarchies.

Table of values

n a(n)
0 1
1 1
2 2
3 6
4 13
5 33
6 78
7 186
8 436
9 1028
10 2394
11 5566
12 12877
13 29689
14 68198
15 156194
16 356599
17 811959
18 1843956
19 4177436
20 9442166
21 21295934
22 47932572
23 107677140
24 241443980
25 540441068
26 1207689636
27 2694452060
28 6002389882
29 13351958546
30 29659179804
31 65794744420
32 145768641091

List of values

[1, 1, 2, 6, 13, 33, 78, 186, 436, 1028, 2394, 5566, 12877, 29689, 68198, 156194, 356599, 811959, 1843956, 4177436, 9442166, 21295934, 47932572, 107677140, 241443980, 540441068, 1207689636, 2694452060, 6002389882, 13351958546, 29659179804, 65794744420, 145768641091]