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.

A348223 a(n) = Sum_{d|n} (-1)^(sigma(d) - 1).

Table of values

n a(n)
1 1
2 2
3 0
4 3
5 0
6 0
7 0
8 4
9 1
10 0
11 0
12 0
13 0
14 0
15 -2
16 5
17 0
18 2
19 0
20 0
21 -2
22 0
23 0
24 0
25 1
26 0
27 0
28 0
29 0
30 -4
31 0
32 6
33 -2
34 0
35 -2
36 3
37 0
38 0
39 -2
40 0
41 0
42 -4
43 0
44 0
45 -2
46 0
47 0
48 0
49 1
50 2
51 -2
52 0
53 0
54 0
55 -2
56 0
57 -2
58 0
59 0
60 -6
61 0
62 0
63 -2
64 7
65 -2
66 -4
67 0
68 0
69 -2
70 -4
71 0
72 4
73 0
74 0
75 -2
76 0
77 -2
78 -4
79 0
80 0
81 1
82 0
83 0
84 -6
85 -2
86 0
87 -2
88 0
89 0
90 -4
91 -2
92 0
93 -2
94 0
95 -2
96 0
97 0
98 2
99 -2
100 3
101 0
102 -4
103 0
104 0
105 -6

List of values

[1, 2, 0, 3, 0, 0, 0, 4, 1, 0, 0, 0, 0, 0, -2, 5, 0, 2, 0, 0, -2, 0, 0, 0, 1, 0, 0, 0, 0, -4, 0, 6, -2, 0, -2, 3, 0, 0, -2, 0, 0, -4, 0, 0, -2, 0, 0, 0, 1, 2, -2, 0, 0, 0, -2, 0, -2, 0, 0, -6, 0, 0, -2, 7, -2, -4, 0, 0, -2, -4, 0, 4, 0, 0, -2, 0, -2, -4, 0, 0, 1, 0, 0, -6, -2, 0, -2, 0, 0, -4, -2, 0, -2, 0, -2, 0, 0, 2, -2, 3, 0, -4, 0, 0, -6]