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.

A316441 a(n) = Sum (-1)^k where the sum is over all factorizations of n into factors > 1 and k is the number of factors.

Table of values

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

List of values

[1, -1, -1, 0, -1, 0, -1, -1, 0, 0, -1, 0, -1, 0, 0, 1, -1, 0, -1, 0, 0, 0, -1, 1, 0, 0, -1, 0, -1, 1, -1, -1, 0, 0, 0, 1, -1, 0, 0, 1, -1, 1, -1, 0, 0, 0, -1, 0, 0, 0, 0, 0, -1, 1, 0, 1, 0, 0, -1, 1, -1, 0, 0, 1, 0, 1, -1, 0, 0, 1, -1, 0, -1, 0, 0, 0, 0, 1, -1]