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.

A099420 Numbers k such that 7*R_k - 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Table of values

n a(n)
1 1
2 2
3 3
4 5
5 9
6 12
7 15
8 21
9 264
10 383
11 2720
12 4494
13 21167
14 45825
15 55851
16 64568
17 70727

List of values

[1, 2, 3, 5, 9, 12, 15, 21, 264, 383, 2720, 4494, 21167, 45825, 55851, 64568, 70727]