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.

A087415 Odd numbers k such that abs(sigma(k)-2k) <= sqrt(k). Abundance-radius = abs(sigma(k)-2k) does not exceed square root of k and k is odd.

Table of values

n a(n)
1 1
2 315
3 945
4 1155
5 2205
6 7425
7 8415
8 8925
9 9405
10 9555
11 24885
12 26145
13 26325
14 28035
15 30555
16 31815
17 32445
18 33705
19 34335
20 35595
21 40005
22 40365
23 41265
24 43155
25 46035
26 49875
27 51765
28 55335
29 78975
30 80535
31 83265
32 91455
33 96915
34 101475
35 106425
36 130815
37 191565
38 338415

List of values

[1, 315, 945, 1155, 2205, 7425, 8415, 8925, 9405, 9555, 24885, 26145, 26325, 28035, 30555, 31815, 32445, 33705, 34335, 35595, 40005, 40365, 41265, 43155, 46035, 49875, 51765, 55335, 78975, 80535, 83265, 91455, 96915, 101475, 106425, 130815, 191565, 338415]

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

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