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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.

A260963 Numbers n such that gcd(sigma(n), n*(n+1)/2 - sigma(n)) = 1, where sigma(n) is sum of positive divisors of n.

Table of values

n a(n)
1 1
2 4
3 9
4 10
5 16
6 21
7 22
8 25
9 34
10 36
11 46
12 49
13 57
14 58
15 64
16 70
17 81
18 82
19 85
20 93
21 94
22 100
23 106
24 118
25 121
26 129
27 130
28 133
29 142
30 144
31 154
32 166
33 169
34 178
35 201
36 202
37 205
38 214
39 217
40 225
41 226
42 237
43 238
44 250
45 253
46 256
47 262
48 265
49 274
50 289
51 298
52 301
53 309
54 310
55 322
56 324
57 325

List of values

[1, 4, 9, 10, 16, 21, 22, 25, 34, 36, 46, 49, 57, 58, 64, 70, 81, 82, 85, 93, 94, 100, 106, 118, 121, 129, 130, 133, 142, 144, 154, 166, 169, 178, 201, 202, 205, 214, 217, 225, 226, 237, 238, 250, 253, 256, 262, 265, 274, 289, 298, 301, 309, 310, 322, 324, 325]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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