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A237838 a(n) = |{0 < k <= n: the number of Sophie Germain primes among 1, ..., k*n is a Sophie Germain prime}|.

Table of values

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

List of values

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

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