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.

A068019 Composite n such that both 1 + phi(n) and -1 + phi(n) are primes, i.e., phi(n) is the middle term between twin primes (A014574).

Table of values

n a(n)
1 8
2 9
3 10
4 12
5 14
6 18
7 21
8 26
9 27
10 28
11 36
12 38
13 42
14 49
15 54
16 62
17 77
18 86
19 91
20 93
21 95
22 98
23 99
24 111
25 117
26 122
27 124
28 133
29 135
30 146
31 148
32 152
33 154
34 171
35 182
36 186
37 189
38 190
39 198
40 206
41 209
42 216
43 217
44 218
45 221
46 222
47 228
48 234
49 252
50 266
51 270
52 278
53 279
54 287
55 291
56 297
57 302

List of values

[8, 9, 10, 12, 14, 18, 21, 26, 27, 28, 36, 38, 42, 49, 54, 62, 77, 86, 91, 93, 95, 98, 99, 111, 117, 122, 124, 133, 135, 146, 148, 152, 154, 171, 182, 186, 189, 190, 198, 206, 209, 216, 217, 218, 221, 222, 228, 234, 252, 266, 270, 278, 279, 287, 291, 297, 302]

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

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