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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.

A331860 Numbers k such that R(k) + 10^floor(k/2-1) is prime, where R(k) = (10^k-1)/9 (repunit: A002275).

Table of values

n a(n)
1 6
2 7
3 12
4 31
5 58
6 127
7 454
8 556
9 558
10 604
11 2944
12 8118
13 12078
14 16942
15 26268
16 45198

List of values

[6, 7, 12, 31, 58, 127, 454, 556, 558, 604, 2944, 8118, 12078, 16942, 26268, 45198]

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

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