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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.

A139557 a(1)=2. For n>=2, a(n) = smallest integer > a(n-1) that is not coprime to n but is coprime to (n+1).

Table of values

n a(n)
1 2
2 4
3 9
4 12
5 25
6 26
7 35
8 38
9 39
10 40
11 55
12 56
13 65
14 68
15 69
16 70
17 85
18 86
19 133
20 134
21 135
22 136
23 161
24 162
25 165
26 166
27 171
28 172
29 203
30 204
31 217
32 218
33 219
34 221
35 235
36 236
37 259
38 262
39 267
40 268
41 451
42 452
43 559
44 562
45 565
46 566
47 611
48 612
49 623
50 625
51 627
52 628
53 689
54 692
55 695
56 698
57 699

List of values

[2, 4, 9, 12, 25, 26, 35, 38, 39, 40, 55, 56, 65, 68, 69, 70, 85, 86, 133, 134, 135, 136, 161, 162, 165, 166, 171, 172, 203, 204, 217, 218, 219, 221, 235, 236, 259, 262, 267, 268, 451, 452, 559, 562, 565, 566, 611, 612, 623, 625, 627, 628, 689, 692, 695, 698, 699]

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

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