A250201 - cp's OEIS frontend

A250201 Least b such that Phi_n(b, b-1) is prime.

n	a(n)
2	2
3	2
4	2
5	2
6	2
7	2
8	2
9	2
10	2
11	6
12	2
13	2
14	2
15	2
16	2
17	2
18	3
19	2
20	3
21	4
22	2
23	6
24	2
25	4
26	2
27	2
28	3
29	3
30	2
31	2
32	2
33	2
34	2
35	4
36	5
37	40
38	2
39	3
40	2
41	7
42	2
43	5
44	3
45	3
46	2
47	13
48	3
49	2
50	14
51	4
52	22
53	3
54	3
55	13
56	2
57	34
58	5
59	3
60	5
61	2
62	2
63	34
64	9
65	2
66	17
67	7
68	3
69	2
70	3
71	18
72	9
73	47
74	4
75	20
76	3
77	2
78	2
79	8
80	2
81	4
82	17
83	6
84	14
85	2
86	2
87	61
88	18
89	2
90	2

[2, 2, 2, 2, 2, 2, 2, 2, 2, 6, 2, 2, 2, 2, 2, 2, 3, 2, 3, 4, 2, 6, 2, 4, 2, 2, 3, 3, 2, 2, 2, 2, 2, 4, 5, 40, 2, 3, 2, 7, 2, 5, 3, 3, 2, 13, 3, 2, 14, 4, 22, 3, 3, 13, 2, 34, 5, 3, 5, 2, 2, 34, 9, 2, 17, 7, 3, 2, 3, 18, 9, 47, 4, 20, 3, 2, 2, 8, 2, 4, 17, 6, 14, 2, 2, 61, 18, 2, 2]

cp's OEIS Frontend

A250201 Least b such that Phi_n(b, b-1) is prime.

Table of values

List of values

n	a(n)
2	2
3	2
4	2
5	2
6	2
7	2
8	2
9	2
10	2
11	6
12	2
13	2
14	2
15	2
16	2
17	2
18	3
19	2
20	3
21	4
22	2
23	6
24	2
25	4
26	2
27	2
28	3
29	3
30	2
31	2
32	2
33	2
34	2
35	4
36	5
37	40
38	2
39	3
40	2
41	7
42	2
43	5
44	3
45	3
46	2
47	13
48	3
49	2
50	14
51	4
52	22
53	3
54	3
55	13
56	2
57	34
58	5
59	3
60	5
61	2
62	2
63	34
64	9
65	2
66	17
67	7
68	3
69	2
70	3
71	18
72	9
73	47
74	4
75	20
76	3
77	2
78	2
79	8
80	2
81	4
82	17
83	6
84	14
85	2
86	2
87	61
88	18
89	2
90	2

n	a(n)
2	2
3	2
4	2
5	2
6	2
7	2
8	2
9	2
10	2
11	6
12	2
13	2
14	2
15	2
16	2
17	2
18	3
19	2
20	3
21	4
22	2
23	6
24	2
25	4
26	2
27	2
28	3
29	3
30	2
31	2
32	2
33	2
34	2
35	4
36	5
37	40
38	2
39	3
40	2
41	7
42	2
43	5
44	3
45	3
46	2
47	13
48	3
49	2
50	14
51	4
52	22
53	3
54	3
55	13
56	2
57	34
58	5
59	3
60	5
61	2
62	2
63	34
64	9
65	2
66	17
67	7
68	3
69	2
70	3
71	18
72	9
73	47
74	4
75	20
76	3
77	2
78	2
79	8
80	2
81	4
82	17
83	6
84	14
85	2
86	2
87	61
88	18
89	2
90	2

n	a(n)
2	2
3	2
4	2
5	2
6	2
7	2
8	2
9	2
10	2
11	6
12	2
13	2
14	2
15	2
16	2
17	2
18	3
19	2
20	3
21	4
22	2
23	6
24	2
25	4
26	2
27	2
28	3
29	3
30	2
31	2
32	2
33	2
34	2
35	4
36	5
37	40
38	2
39	3
40	2
41	7
42	2
43	5
44	3
45	3
46	2
47	13
48	3
49	2
50	14
51	4
52	22
53	3
54	3
55	13
56	2
57	34
58	5
59	3
60	5
61	2
62	2
63	34
64	9
65	2
66	17
67	7
68	3
69	2
70	3
71	18
72	9
73	47
74	4
75	20
76	3
77	2
78	2
79	8
80	2
81	4
82	17
83	6
84	14
85	2
86	2
87	61
88	18
89	2
90	2