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.

A343370 a(1) = 1; a(n) = Sum_{d|n, d < n} (-1)^d * a(d).

Table of values

n a(n)
1 1
2 -1
3 -1
4 -2
5 -1
6 -1
7 -1
8 -4
9 0
10 -1
11 -1
12 -4
13 -1
14 -1
15 1
16 -8
17 -1
18 -2
19 -1
20 -4
21 1
22 -1
23 -1
24 -12
25 0
26 -1
27 0
28 -4
29 -1
30 -3
31 -1
32 -16
33 1
34 -1
35 1
36 -10
37 -1
38 -1
39 1
40 -12
41 -1
42 -3
43 -1
44 -4
45 0
46 -1
47 -1
48 -32
49 0
50 -2
51 1
52 -4
53 -1
54 -4
55 1
56 -12
57 1
58 -1
59 -1
60 -16
61 -1
62 -1
63 0
64 -32
65 1
66 -3
67 -1
68 -4
69 1
70 -3
71 -1
72 -36
73 -1
74 -1
75 0
76 -4
77 1
78 -3
79 -1
80 -32
81 0

List of values

[1, -1, -1, -2, -1, -1, -1, -4, 0, -1, -1, -4, -1, -1, 1, -8, -1, -2, -1, -4, 1, -1, -1, -12, 0, -1, 0, -4, -1, -3, -1, -16, 1, -1, 1, -10, -1, -1, 1, -12, -1, -3, -1, -4, 0, -1, -1, -32, 0, -2, 1, -4, -1, -4, 1, -12, 1, -1, -1, -16, -1, -1, 0, -32, 1, -3, -1, -4, 1, -3, -1, -36, -1, -1, 0, -4, 1, -3, -1, -32, 0]