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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.

A227770 Bertrand primes II: a(n) is the largest prime < 2*a(n-1)-2.

Table of values

n a(n)
1 5
2 7
3 11
4 19
5 31
6 59
7 113
8 223
9 443
10 883
11 1759
12 3511
13 7019
14 14033
15 28057
16 56101
17 112199
18 224363
19 448703
20 897401
21 1794787
22 3589571
23 7179127
24 14358247
25 28716487
26 57432961
27 114865903
28 229731787
29 459463553
30 918927083
31 1837854119
32 3675708217
33 7351416419
34 14702832827
35 29405665651
36 58811331281
37 117622662557
38 235245325061
39 470490650107
40 940981300211
41 1881962600417

List of values

[5, 7, 11, 19, 31, 59, 113, 223, 443, 883, 1759, 3511, 7019, 14033, 28057, 56101, 112199, 224363, 448703, 897401, 1794787, 3589571, 7179127, 14358247, 28716487, 57432961, 114865903, 229731787, 459463553, 918927083, 1837854119, 3675708217, 7351416419, 14702832827, 29405665651, 58811331281, 117622662557, 235245325061, 470490650107, 940981300211, 1881962600417]

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

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