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.

A334890 a(1) = 1; a(n) = -Sum_{d|n, d > 1} (sigma(d) - d) * a(n/d).

Table of values

n a(n)
1 1
2 -1
3 -1
4 -2
5 -1
6 -4
7 -1
8 -2
9 -3
10 -6
11 -1
12 -1
13 -1
14 -8
15 -7
16 0
17 -1
18 -4
19 -1
20 -3
21 -9
22 -12
23 -1
24 14
25 -5
26 -14
27 -6
28 -5
29 -1
30 -2
31 -1
32 4
33 -13
34 -18
35 -11
36 28
37 -1
38 -20
39 -15
40 18
41 -1
42 -6
43 -1
44 -9
45 -10
46 -24
47 -1
48 36
49 -7
50 -18
51 -19
52 -11
53 -1
54 12
55 -15
56 22
57 -21
58 -30
59 -1
60 85
61 -1
62 -32
63 -14
64 8
65 -17

List of values

[1, -1, -1, -2, -1, -4, -1, -2, -3, -6, -1, -1, -1, -8, -7, 0, -1, -4, -1, -3, -9, -12, -1, 14, -5, -14, -6, -5, -1, -2, -1, 4, -13, -18, -11, 28, -1, -20, -15, 18, -1, -6, -1, -9, -10, -24, -1, 36, -7, -18, -19, -11, -1, 12, -15, 22, -21, -30, -1, 85, -1, -32, -14, 8, -17]