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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.

A237453 Number of primes p < n with p*n + pi(p) prime, where pi(.) is given by A000720.

Table of values

n a(n)
1 0
2 0
3 1
4 0
5 2
6 1
7 1
8 2
9 3
10 1
11 1
12 1
13 1
14 2
15 3
16 2
17 2
18 2
19 2
20 3
21 2
22 1
23 2
24 1
25 2
26 3
27 3
28 2
29 3
30 1
31 1
32 1
33 3
34 2
35 4
36 3
37 3
38 3
39 2
40 1
41 2
42 1
43 1
44 3
45 3
46 1
47 2
48 3
49 3
50 3
51 4
52 3
53 3
54 2
55 2
56 6
57 4
58 3
59 5
60 3
61 2
62 3
63 2
64 4
65 4
66 3
67 1
68 3
69 5
70 2
71 5
72 3
73 1
74 2
75 3
76 2
77 4
78 2
79 3
80 2

List of values

[0, 0, 1, 0, 2, 1, 1, 2, 3, 1, 1, 1, 1, 2, 3, 2, 2, 2, 2, 3, 2, 1, 2, 1, 2, 3, 3, 2, 3, 1, 1, 1, 3, 2, 4, 3, 3, 3, 2, 1, 2, 1, 1, 3, 3, 1, 2, 3, 3, 3, 4, 3, 3, 2, 2, 6, 4, 3, 5, 3, 2, 3, 2, 4, 4, 3, 1, 3, 5, 2, 5, 3, 1, 2, 3, 2, 4, 2, 3, 2]

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