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.

A056700 Numbers k such that 2*10^k + R_k is prime, where R_k = 11...1 is the repunit (A002275) of length k.

Table of values

n a(n)
1 0
2 2
3 3
4 12
5 18
6 23
7 57
8 128
9 543
10 584
11 833
12 2450
13 2810
14 2873
15 3671
16 6384
17 10296
18 16704
19 53049
20 56544
21 74253

List of values

[0, 2, 3, 12, 18, 23, 57, 128, 543, 584, 833, 2450, 2810, 2873, 3671, 6384, 10296, 16704, 53049, 56544, 74253]