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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.

A333338 Numbers k such that sigma_2(k) = sigma_2(phi(k)).

Table of values

n a(n)
1 1
2 7
3 11891
4 130801
5 273493
6 1438811
7 3008423
8 6290339
9 15826921
10 33092653
11 69193729
12 144677797
13 174096131
14 364019183
15 761131019
16 1591455767
17 1915057441
18 3327589331
19 4004211013
20 8372441209
21 17506013437
22 21065631851
23 36603482641
24 44046321143
25 76534554613
26 92096853299

List of values

[1, 7, 11891, 130801, 273493, 1438811, 3008423, 6290339, 15826921, 33092653, 69193729, 144677797, 174096131, 364019183, 761131019, 1591455767, 1915057441, 3327589331, 4004211013, 8372441209, 17506013437, 21065631851, 36603482641, 44046321143, 76534554613, 92096853299]

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

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