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.

A130030 a(n) = Sum_{d|n} (-1)^omega(n/d) * phi(rad(n/d)) * prime(d).

Table of values

n a(n)
1 2
2 1
3 1
4 2
5 3
6 6
7 5
8 7
9 9
10 14
11 11
12 15
13 17
14 20
15 21
16 22
17 27
18 20
19 31
20 23
21 33
22 38
23 39
24 20
25 45
26 48
27 43
28 35
29 53
30 6
31 67
32 47
33 65
34 64
35 63
36 25
37 85
38 78
39 73
40 34
41 99
42 20
43 107
44 63
45 45
46 94
47 119
48 35
49 113
50 56
51 99
52 73
53 137
54 54
55 103
56 54
57 117
58 134
59 161
60 -1
61 163
62 136
63 73
64 96
65 113
66 24
67 199
68 107
69 159
70 12
71 213

List of values

[2, 1, 1, 2, 3, 6, 5, 7, 9, 14, 11, 15, 17, 20, 21, 22, 27, 20, 31, 23, 33, 38, 39, 20, 45, 48, 43, 35, 53, 6, 67, 47, 65, 64, 63, 25, 85, 78, 73, 34, 99, 20, 107, 63, 45, 94, 119, 35, 113, 56, 99, 73, 137, 54, 103, 54, 117, 134, 161, -1, 163, 136, 73, 96, 113, 24, 199, 107, 159, 12, 213]