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.

A280192 Triangle read by rows: T(n,k) = number of topologies on an n-set X such that there are exactly k elements in X that are topologically distinguishable, n >= 0, 0 <= k <= n.

Table of values

n a(n)
0 1
1 0
2 1
3 1
4 0
5 3
6 1
7 9
8 0
9 19
10 10
11 12
12 114
13 0
14 219
15 31
16 300
17 190
18 2190
19 0
20 4231
21 361
22 1158
23 10140
24 4380
25 63465
26 0
27 130023
28 2164
29 26341
30 46389
31 451920
32 148085
33 2730483
34 0
35 6129859
36 32663
37 192496
38 1930852
39 2381624
40 27601000
41 7281288
42 171636052
43 0
44 431723379

List of values

[1, 0, 1, 1, 0, 3, 1, 9, 0, 19, 10, 12, 114, 0, 219, 31, 300, 190, 2190, 0, 4231, 361, 1158, 10140, 4380, 63465, 0, 130023, 2164, 26341, 46389, 451920, 148085, 2730483, 0, 6129859, 32663, 192496, 1930852, 2381624, 27601000, 7281288, 171636052, 0, 431723379]