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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.

A209494 Smallest prime p such that 2p*n^2 - 1 is prime, or 0 if no such prime exists.

Table of values

n a(n)
1 2
2 3
3 3
4 7
5 3
6 5
7 3
8 3
9 5
10 3
11 7
12 3
13 3
14 37
15 13
16 7
17 3
18 11
19 31
20 3
21 5
22 3
23 19
24 11
25 13
26 7
27 3
28 3
29 19
30 3
31 31
32 3
33 5
34 7
35 3
36 5
37 13
38 3
39 11
40 37
41 61
42 13
43 3
44 7
45 3
46 19
47 73
48 5
49 7
50 19
51 11
52 3
53 31
54 7
55 3
56 31
57 31
58 3
59 7
60 3
61 19
62 3
63 3
64 31
65 3
66 19
67 151
68 3
69 5
70 3
71 7
72 5
73 3
74 97

List of values

[2, 3, 3, 7, 3, 5, 3, 3, 5, 3, 7, 3, 3, 37, 13, 7, 3, 11, 31, 3, 5, 3, 19, 11, 13, 7, 3, 3, 19, 3, 31, 3, 5, 7, 3, 5, 13, 3, 11, 37, 61, 13, 3, 7, 3, 19, 73, 5, 7, 19, 11, 3, 31, 7, 3, 31, 31, 3, 7, 3, 19, 3, 3, 31, 3, 19, 151, 3, 5, 3, 7, 5, 3, 97]

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