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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.

A054547 Triangular array giving number of labeled digraphs on n unisolated nodes and k=0..n*(n-1) arcs.

Table of values

n a(n)
1 0
2 0
3 2
4 1
5 0
6 0
7 12
8 20
9 15
10 6
11 1
12 0
13 0
14 12
15 140
16 435
17 768
18 920
19 792
20 495
21 220
22 66
23 12
24 1
25 0
26 0
27 0
28 240
29 2520
30 11604
31 34150
32 73560
33 123495
34 166860
35 184426
36 167900
37 125965
38 77520
39 38760
40 15504
41 4845
42 1140
43 190
44 20
45 1

List of values

[0, 0, 2, 1, 0, 0, 12, 20, 15, 6, 1, 0, 0, 12, 140, 435, 768, 920, 792, 495, 220, 66, 12, 1, 0, 0, 0, 240, 2520, 11604, 34150, 73560, 123495, 166860, 184426, 167900, 125965, 77520, 38760, 15504, 4845, 1140, 190, 20, 1]

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

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