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.

A331865 Numbers n for which R(n) + 2*10^floor(n/2) is prime, where R(n) = (10^n-1)/9.

Table of values

n a(n)
1 0
2 1
3 2
4 3
5 5
6 6
7 8
8 12
9 20
10 39
11 74
12 78
13 80
14 84
15 104
16 195
17 654
18 980
19 2076
20 5940
21 19637

List of values

[0, 1, 2, 3, 5, 6, 8, 12, 20, 39, 74, 78, 80, 84, 104, 195, 654, 980, 2076, 5940, 19637]