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.

A086831 Ramanujan sum c_n(2).

Table of values

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

List of values

[1, 1, -1, -2, -1, -1, -1, 0, 0, -1, -1, 2, -1, -1, 1, 0, -1, 0, -1, 2, 1, -1, -1, 0, 0, -1, 0, 2, -1, 1, -1, 0, 1, -1, 1, 0, -1, -1, 1, 0, -1, 1, -1, 2, 0, -1, -1, 0, 0, 0, 1, 2, -1, 0, 1, 0, 1, -1, -1, -2, -1, -1, 0, 0, 1, 1, -1, 2, 1, 1, -1, 0, -1, -1, 0, 2, 1, 1, -1, 0, 0, -1, -1, -2, 1, -1, 1, 0, -1, 0, 1, 2, 1, -1, 1, 0, -1, 0, 0, 0, -1, 1, -1, 0, -1]