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.

A272981 Least prime k>1 such that the sum of divisors of powers k^e, 1 <= e <= n, are divisible by the number their divisors, d(k^e).

Table of values

n a(n)
1 3
2 7
3 7
4 31
5 31
6 211
7 211
8 211
9 211
10 2311
11 2311
12 120121
13 120121
14 120121
15 120121
16 4084081
17 4084081
18 106696591
19 106696591
20 106696591
21 106696591
22 892371481
23 892371481
24 892371481
25 892371481
26 892371481
27 892371481
28 71166625531
29 71166625531
30 200560490131
31 200560490131

List of values

[3, 7, 7, 31, 31, 211, 211, 211, 211, 2311, 2311, 120121, 120121, 120121, 120121, 4084081, 4084081, 106696591, 106696591, 106696591, 106696591, 892371481, 892371481, 892371481, 892371481, 892371481, 892371481, 71166625531, 71166625531, 200560490131, 200560490131]

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

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