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.

A348515 a(n) = Sum_{d|n, d <= sqrt(n)} (-1)^(n/d + 1).

Table of values

n a(n)
1 1
2 -1
3 1
4 -2
5 1
6 0
7 1
8 -2
9 2
10 0
11 1
12 -3
13 1
14 0
15 2
16 -3
17 1
18 -1
19 1
20 -1
21 2
22 0
23 1
24 -4
25 2
26 0
27 2
28 -1
29 1
30 -2
31 1
32 -3
33 2
34 0
35 2
36 -3
37 1
38 0
39 2
40 -4
41 1
42 0
43 1
44 -1
45 3
46 0
47 1
48 -5
49 2
50 -1
51 2
52 -1
53 1
54 0
55 2
56 -4
57 2
58 0
59 1
60 -4
61 1
62 0
63 3
64 -4
65 2
66 0
67 1
68 -1
69 2
70 -2
71 1
72 -4
73 1
74 0
75 3
76 -1
77 2
78 0
79 1
80 -5

List of values

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