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.

A219570 Triangular array read by rows. T(n,k) is the number of necklaces (turning over is not allowed) of n labeled black or white beads having exactly k black beads.

Table of values

n a(n)
0 0
1 1
2 1
3 1
4 2
5 1
6 2
7 6
8 6
9 2
10 6
11 24
12 36
13 24
14 6
15 24
16 120
17 240
18 240
19 120
20 24
21 120
22 720
23 1800
24 2400
25 1800
26 720
27 120
28 720
29 5040
30 15120
31 25200
32 25200
33 15120
34 5040
35 720
36 5040
37 40320
38 141120
39 282240
40 352800
41 282240
42 141120
43 40320
44 5040
45 40320
46 362880
47 1451520
48 3386880
49 5080320
50 5080320
51 3386880
52 1451520
53 362880
54 40320

List of values

[0, 1, 1, 1, 2, 1, 2, 6, 6, 2, 6, 24, 36, 24, 6, 24, 120, 240, 240, 120, 24, 120, 720, 1800, 2400, 1800, 720, 120, 720, 5040, 15120, 25200, 25200, 15120, 5040, 720, 5040, 40320, 141120, 282240, 352800, 282240, 141120, 40320, 5040, 40320, 362880, 1451520, 3386880, 5080320, 5080320, 3386880, 1451520, 362880, 40320]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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