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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.

A368736 a(n) = Sum_{k = 1..n} gcd(2*k+1, n).

Table of values

n a(n)
1 1
2 2
3 5
4 4
5 9
6 10
7 13
8 8
9 21
10 18
11 21
12 20
13 25
14 26
15 45
16 16
17 33
18 42
19 37
20 36
21 65
22 42
23 45
24 40
25 65
26 50
27 81
28 52
29 57
30 90
31 61
32 32
33 105
34 66
35 117
36 84
37 73
38 74
39 125
40 72
41 81
42 130
43 85
44 84
45 189
46 90
47 93
48 80
49 133
50 130
51 165
52 100
53 105
54 162
55 189
56 104
57 185
58 114
59 117
60 180
61 121
62 122
63 273
64 64
65 225
66 210
67 133
68 132
69 225
70 234

List of values

[1, 2, 5, 4, 9, 10, 13, 8, 21, 18, 21, 20, 25, 26, 45, 16, 33, 42, 37, 36, 65, 42, 45, 40, 65, 50, 81, 52, 57, 90, 61, 32, 105, 66, 117, 84, 73, 74, 125, 72, 81, 130, 85, 84, 189, 90, 93, 80, 133, 130, 165, 100, 105, 162, 189, 104, 185, 114, 117, 180, 121, 122, 273, 64, 225, 210, 133, 132, 225, 234]

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

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