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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.

A211780 a(n) = Sum_{d|n, d d * tau(n / d), where tau = A000005 is the number of divisors.

Table of values

n a(n)
1 0
2 2
3 2
4 7
5 2
6 14
7 2
8 18
9 9
10 18
11 2
12 43
13 2
14 22
15 20
16 41
17 2
18 54
19 2
20 57
21 24
22 30
23 2
24 106
25 13
26 34
27 31
28 71
29 2
30 110
31 2
32 88
33 32
34 42
35 28
36 162
37 2
38 46
39 36
40 142
41 2
42 138
43 2
44 99
45 81
46 54
47 2
48 237
49 17
50 102
51 44
52 113
53 2
54 178
55 36
56 178
57 48
58 66
59 2
60 325
61 2
62 70
63 99
64 183
65 40
66 194
67 2

List of values

[0, 2, 2, 7, 2, 14, 2, 18, 9, 18, 2, 43, 2, 22, 20, 41, 2, 54, 2, 57, 24, 30, 2, 106, 13, 34, 31, 71, 2, 110, 2, 88, 32, 42, 28, 162, 2, 46, 36, 142, 2, 138, 2, 99, 81, 54, 2, 237, 17, 102, 44, 113, 2, 178, 36, 178, 48, 66, 2, 325, 2, 70, 99, 183, 40, 194, 2]

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

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