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.

A191249 Triangular array T(n,k) read by rows: number of labeled relations of the n-set with exactly k connected components.

Table of values

n a(n)
1 2
2 12
3 4
4 432
5 72
6 8
7 61344
8 3888
9 288
10 16
11 32866560
12 665280
13 21600
14 960
15 32
16 68307743232
17 407306880
18 4328640
19 95040
20 2880
21 64
22 561981464819712
23 965518299648
24 2948037120
25 21893760
26 362880
27 8064
28 128

List of values

[2, 12, 4, 432, 72, 8, 61344, 3888, 288, 16, 32866560, 665280, 21600, 960, 32, 68307743232, 407306880, 4328640, 95040, 2880, 64, 561981464819712, 965518299648, 2948037120, 21893760, 362880, 8064, 128]

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

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