A341670 - cp's OEIS frontend

A341670 a(n) is conjecturally the largest prime p such that, for every prime q > p, q^n - 1 has more divisors than does p^n - 1, or -1 if no such prime p exists.

n	a(n)
1	5
2	73
3	5
4	101
5	3
6	167
7	5
8	71
9	3
10	43
11	5
12	167
13	5
14	73
15	3
16	19
17	2
18	17
19	2
20	19
21	3
22	23
23	2
24	71
25	2
26	7
27	2
28	29
29	-1
30	13
31	2
32	11
33	2
34	7
35	2
36	13
37	2
38	3
39	2
40	11
41	2
42	7
43	-1
44	23
45	2
46	17
47	5
48	17
49	5
50	7
51	-1
52	7
53	-1
54	11
55	-1
56	5
57	2
58	7
59	2
60	11
61	2
62	2
63	3
64	3
65	2
66	5
67	2
68	2
69	2
70	3
71	3
72	11
73	-1
74	2
75	-1
76	7

[5, 73, 5, 101, 3, 167, 5, 71, 3, 43, 5, 167, 5, 73, 3, 19, 2, 17, 2, 19, 3, 23, 2, 71, 2, 7, 2, 29, -1, 13, 2, 11, 2, 7, 2, 13, 2, 3, 2, 11, 2, 7, -1, 23, 2, 17, 5, 17, 5, 7, -1, 7, -1, 11, -1, 5, 2, 7, 2, 11, 2, 2, 3, 3, 2, 5, 2, 2, 2, 3, 3, 11, -1, 2, -1, 7]

cp's OEIS Frontend

A341670 a(n) is conjecturally the largest prime p such that, for every prime q > p, q^n - 1 has more divisors than does p^n - 1, or -1 if no such prime p exists.

Table of values

List of values

n	a(n)
1	5
2	73
3	5
4	101
5	3
6	167
7	5
8	71
9	3
10	43
11	5
12	167
13	5
14	73
15	3
16	19
17	2
18	17
19	2
20	19
21	3
22	23
23	2
24	71
25	2
26	7
27	2
28	29
29	-1
30	13
31	2
32	11
33	2
34	7
35	2
36	13
37	2
38	3
39	2
40	11
41	2
42	7
43	-1
44	23
45	2
46	17
47	5
48	17
49	5
50	7
51	-1
52	7
53	-1
54	11
55	-1
56	5
57	2
58	7
59	2
60	11
61	2
62	2
63	3
64	3
65	2
66	5
67	2
68	2
69	2
70	3
71	3
72	11
73	-1
74	2
75	-1
76	7

n	a(n)
1	5
2	73
3	5
4	101
5	3
6	167
7	5
8	71
9	3
10	43
11	5
12	167
13	5
14	73
15	3
16	19
17	2
18	17
19	2
20	19
21	3
22	23
23	2
24	71
25	2
26	7
27	2
28	29
29	-1
30	13
31	2
32	11
33	2
34	7
35	2
36	13
37	2
38	3
39	2
40	11
41	2
42	7
43	-1
44	23
45	2
46	17
47	5
48	17
49	5
50	7
51	-1
52	7
53	-1
54	11
55	-1
56	5
57	2
58	7
59	2
60	11
61	2
62	2
63	3
64	3
65	2
66	5
67	2
68	2
69	2
70	3
71	3
72	11
73	-1
74	2
75	-1
76	7

n	a(n)
1	5
2	73
3	5
4	101
5	3
6	167
7	5
8	71
9	3
10	43
11	5
12	167
13	5
14	73
15	3
16	19
17	2
18	17
19	2
20	19
21	3
22	23
23	2
24	71
25	2
26	7
27	2
28	29
29	-1
30	13
31	2
32	11
33	2
34	7
35	2
36	13
37	2
38	3
39	2
40	11
41	2
42	7
43	-1
44	23
45	2
46	17
47	5
48	17
49	5
50	7
51	-1
52	7
53	-1
54	11
55	-1
56	5
57	2
58	7
59	2
60	11
61	2
62	2
63	3
64	3
65	2
66	5
67	2
68	2
69	2
70	3
71	3
72	11
73	-1
74	2
75	-1
76	7