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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.

A055681 Numbers k that divide sigma(k)-phi(k).

Table of values

n a(n)
1 1
2 2
3 12
4 42
5 1242
6 75960
7 1447488
8 3506976
9 6137440
10 10834488
11 17156160
12 90288000
13 431440416
14 454460160
15 704592000
16 1385119360
17 1588268480
18 10674673152
19 24913095480
20 31103703540
21 56015374080
22 80767843200
23 129631788000
24 463308768000
25 469897798656
26 834460413696

List of values

[1, 2, 12, 42, 1242, 75960, 1447488, 3506976, 6137440, 10834488, 17156160, 90288000, 431440416, 454460160, 704592000, 1385119360, 1588268480, 10674673152, 24913095480, 31103703540, 56015374080, 80767843200, 129631788000, 463308768000, 469897798656, 834460413696]

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

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