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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.

A260880 Smallest k such that 1000...0//k (concatenation of 10^n and k) is prime.

Table of values

n a(n)
0 1
1 1
2 9
3 7
4 3
5 3
6 37
7 7
8 7
9 19
10 3
11 37
12 31
13 37
14 61
15 13
16 3
17 3
18 39
19 139
20 57
21 9
22 49
23 7
24 67
25 331
26 319
27 211
28 57
29 33
30 49
31 61
32 103
33 69
34 67
35 43
36 321
37 37
38 3
39 169
40 63
41 57
42 31
43 121
44 9
45 33
46 217
47 69
48 9
49 327
50 171
51 157
52 31
53 21
54 279
55 3
56 193
57 19
58 67
59 7
60 121
61 399
62 57
63 49
64 49
65 49

List of values

[1, 1, 9, 7, 3, 3, 37, 7, 7, 19, 3, 37, 31, 37, 61, 13, 3, 3, 39, 139, 57, 9, 49, 7, 67, 331, 319, 211, 57, 33, 49, 61, 103, 69, 67, 43, 321, 37, 3, 169, 63, 57, 31, 121, 9, 33, 217, 69, 9, 327, 171, 157, 31, 21, 279, 3, 193, 19, 67, 7, 121, 399, 57, 49, 49, 49]

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

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