A299148 - cp's OEIS frontend

A299148 a(n) is the smallest number k such that sigma(k) and sigma(k^n) are both primes.

n	a(n)
1	2
2	2
3	4
4	2
5	25
6	2
7	262144
8	4
9	4
10	64
11	734449
12	2
13	3100870943041
14	9066121
15	4
16	2
17	729
18	2
19	214355670008317962105386619478205641151753401
20	5041
21	64
22	16
23	25
24	10651330026288961
25	16610312161
26	2607021481
27	38950081
28	1817762776525603445521
29	5331481
30	2
31	2160067977820518171249529658520145004718584607049
32	21203610154988994565561

[2, 2, 4, 2, 25, 2, 262144, 4, 4, 64, 734449, 2, 3100870943041, 9066121, 4, 2, 729, 2, 214355670008317962105386619478205641151753401, 5041, 64, 16, 25, 10651330026288961, 16610312161, 2607021481, 38950081, 1817762776525603445521, 5331481, 2, 2160067977820518171249529658520145004718584607049, 21203610154988994565561]

cp's OEIS Frontend

A299148 a(n) is the smallest number k such that sigma(k) and sigma(k^n) are both primes.

Table of values

List of values