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.

A307778 a(1) = 1; a(n+1) = Sum_{d|n} (-1)^(d+1)*a(d).

Table of values

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

List of values

[1, 1, 0, 1, -1, 0, 0, 1, -2, -1, 0, 1, -2, -1, 1, 1, -3, -2, 0, 1, -2, -1, 1, 2, -5, -5, 3, 2, -2, -1, 2, 3, -6, -5, 2, 2, -4, -3, 3, 2, -5, -4, 3, 4, -4, -5, 6, 7, -13, -12, 7, 5, -3, -2, 5, 5, -8, -7, 5, 6, -7, -6, 8, 5, -11, -13, 8, 9, -8, -6, 9, 10, -17, -16, 12, 8, -6]