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.

A330055 Number of non-isomorphic set-systems of weight n with no singletons or endpoints.

Table of values

n a(n)
0 1
1 0
2 0
3 0
4 0
5 0
6 1
7 1
8 3
9 5
10 16
11 24
12 90
13 179
14 567
15 1475
16 4623
17 13650
18 44475
19 144110
20 492017
21 1706956
22 6124330
23 22442687
24 84406276
25 324298231
26 1273955153
27 5106977701
28 20885538133
29 87046940269
30 369534837538
31 1596793560371
32 7019424870960
33 31374394197536
34 142514998263015

List of values

[1, 0, 0, 0, 0, 0, 1, 1, 3, 5, 16, 24, 90, 179, 567, 1475, 4623, 13650, 44475, 144110, 492017, 1706956, 6124330, 22442687, 84406276, 324298231, 1273955153, 5106977701, 20885538133, 87046940269, 369534837538, 1596793560371, 7019424870960, 31374394197536, 142514998263015]