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.

A015713 Numbers m such that phi(m) * sigma(m) + k^2 is not a square for any k.

Table of values

n a(n)
1 4
2 9
3 18
4 49
5 81
6 98
7 121
8 162
9 242
10 361
11 529
12 722
13 729
14 961
15 1058
16 1458
17 1849
18 1922
19 2209
20 2401
21 3481
22 3698
23 4418
24 4489
25 4802
26 5041
27 6241
28 6561
29 6889
30 6962
31 8978
32 10082
33 10609
34 11449
35 12482
36 13122
37 13778
38 14641
39 16129
40 17161

List of values

[4, 9, 18, 49, 81, 98, 121, 162, 242, 361, 529, 722, 729, 961, 1058, 1458, 1849, 1922, 2209, 2401, 3481, 3698, 4418, 4489, 4802, 5041, 6241, 6561, 6889, 6962, 8978, 10082, 10609, 11449, 12482, 13122, 13778, 14641, 16129, 17161]