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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.

A067709 Numbers k such that phi(2*sigma(k)) = 2*sigma(phi(k)).

Table of values

n a(n)
1 2
2 4
3 16
4 18
5 64
6 100
7 450
8 516
9 1458
10 4096
11 4624
12 13932
13 14406
14 20124
15 21780
16 28900
17 29262
18 29616
19 36450
20 45996
21 62500
22 65536
23 92778
24 95916
25 106092
26 106308
27 114630
28 114930
29 121872
30 125652
31 130050
32 140130
33 145794
34 149124
35 160986
36 179562
37 185100

List of values

[2, 4, 16, 18, 64, 100, 450, 516, 1458, 4096, 4624, 13932, 14406, 20124, 21780, 28900, 29262, 29616, 36450, 45996, 62500, 65536, 92778, 95916, 106092, 106308, 114630, 114930, 121872, 125652, 130050, 140130, 145794, 149124, 160986, 179562, 185100]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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