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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.

A057775 a(n) is the least prime p such that p-1 is divisible by 2^n and not by 2^(n+1).

Table of values

n a(n)
0 2
1 3
2 5
3 41
4 17
5 97
6 193
7 641
8 257
9 7681
10 13313
11 18433
12 12289
13 40961
14 114689
15 163841
16 65537
17 1179649
18 786433
19 5767169
20 7340033
21 23068673
22 104857601
23 377487361
24 754974721
25 167772161
26 469762049
27 2013265921
28 3489660929
29 12348030977
30 3221225473
31 75161927681

List of values

[2, 3, 5, 41, 17, 97, 193, 641, 257, 7681, 13313, 18433, 12289, 40961, 114689, 163841, 65537, 1179649, 786433, 5767169, 7340033, 23068673, 104857601, 377487361, 754974721, 167772161, 469762049, 2013265921, 3489660929, 12348030977, 3221225473, 75161927681]

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

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