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.

A113930 Numbers k such that sigma(k) and phi(k) are both triangular numbers.

Table of values

n a(n)
1 1
2 2
3 22
4 3051
5 3219
6 3393
7 5057
8 8653
9 75618
10 95675
11 100503
12 102949
13 104714
14 287826
15 438547
16 522339
17 537159
18 688050
19 2191200
20 2317118
21 2418548
22 2507683
23 2599128
24 3212964
25 4534573
26 5367797
27 6047913
28 6302639
29 7689149
30 13758296
31 14380145
32 15342050
33 16148979

List of values

[1, 2, 22, 3051, 3219, 3393, 5057, 8653, 75618, 95675, 100503, 102949, 104714, 287826, 438547, 522339, 537159, 688050, 2191200, 2317118, 2418548, 2507683, 2599128, 3212964, 4534573, 5367797, 6047913, 6302639, 7689149, 13758296, 14380145, 15342050, 16148979]

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

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