cp's OEIS Frontend

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.

A102931 Numbers k such that 10^k + 2*R_k + 7 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Table of values

n a(n)
1 1
2 3
3 6
4 51
5 57
6 63
7 150
8 393
9 420
10 547
11 42024
12 43063
13 101613
14 107385

List of values

[1, 3, 6, 51, 57, 63, 150, 393, 420, 547, 42024, 43063, 101613, 107385]