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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.

A115909 Numbers k such that sigma(k)*k is a triangular number.

Table of values

n a(n)
1 1
2 2
3 4
4 8
5 16
6 32
7 57
8 64
9 65
10 85
11 87
12 128
13 256
14 512
15 1024
16 1245
17 1421
18 2048
19 3146
20 3330
21 3790
22 4096
23 6695
24 7257
25 8192
26 10137
27 16384
28 25884
29 32768
30 34420
31 34551
32 34947
33 65536
34 131072
35 208495
36 262144
37 348161
38 440495
39 524288
40 530270
41 534430

List of values

[1, 2, 4, 8, 16, 32, 57, 64, 65, 85, 87, 128, 256, 512, 1024, 1245, 1421, 2048, 3146, 3330, 3790, 4096, 6695, 7257, 8192, 10137, 16384, 25884, 32768, 34420, 34551, 34947, 65536, 131072, 208495, 262144, 348161, 440495, 524288, 530270, 534430]

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

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