A374167 - cp's OEIS frontend

A374167 a(n) is the largest k such that the binary representation of prime(n), when interpreted as a base-b number, yields a prime for every b in 2..k.

n	a(n)
1	3
2	2
3	2
4	3
5	3
6	3
7	2
8	2
9	2
10	2
11	2
12	2
13	3
14	2
15	4
16	2
17	2
18	2
19	3
20	2
21	3
22	3
23	2
24	2
25	2
26	2
27	2
28	2
29	3
30	2
31	3
32	2
33	2
34	2
35	2
36	5
37	2
38	2
39	2
40	5
41	2
42	5
43	5
44	3
45	2
46	2
47	3
48	3
49	3
50	4
51	5
52	2
53	2
54	3
55	2
56	2
57	2
58	2
59	2
60	2
61	3
62	2
63	2
64	2
65	2
66	2
67	3
68	2
69	2
70	2
71	2
72	2
73	3
74	2
75	2
76	2
77	2
78	2
79	2
80	2
81	2
82	3
83	2
84	2
85	2
86	5
87	2

[3, 2, 2, 3, 3, 3, 2, 2, 2, 2, 2, 2, 3, 2, 4, 2, 2, 2, 3, 2, 3, 3, 2, 2, 2, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 5, 2, 2, 2, 5, 2, 5, 5, 3, 2, 2, 3, 3, 3, 4, 5, 2, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 5, 2]

cp's OEIS Frontend

A374167 a(n) is the largest k such that the binary representation of prime(n), when interpreted as a base-b number, yields a prime for every b in 2..k.

Table of values

List of values

n	a(n)
1	3
2	2
3	2
4	3
5	3
6	3
7	2
8	2
9	2
10	2
11	2
12	2
13	3
14	2
15	4
16	2
17	2
18	2
19	3
20	2
21	3
22	3
23	2
24	2
25	2
26	2
27	2
28	2
29	3
30	2
31	3
32	2
33	2
34	2
35	2
36	5
37	2
38	2
39	2
40	5
41	2
42	5
43	5
44	3
45	2
46	2
47	3
48	3
49	3
50	4
51	5
52	2
53	2
54	3
55	2
56	2
57	2
58	2
59	2
60	2
61	3
62	2
63	2
64	2
65	2
66	2
67	3
68	2
69	2
70	2
71	2
72	2
73	3
74	2
75	2
76	2
77	2
78	2
79	2
80	2
81	2
82	3
83	2
84	2
85	2
86	5
87	2

n	a(n)
1	3
2	2
3	2
4	3
5	3
6	3
7	2
8	2
9	2
10	2
11	2
12	2
13	3
14	2
15	4
16	2
17	2
18	2
19	3
20	2
21	3
22	3
23	2
24	2
25	2
26	2
27	2
28	2
29	3
30	2
31	3
32	2
33	2
34	2
35	2
36	5
37	2
38	2
39	2
40	5
41	2
42	5
43	5
44	3
45	2
46	2
47	3
48	3
49	3
50	4
51	5
52	2
53	2
54	3
55	2
56	2
57	2
58	2
59	2
60	2
61	3
62	2
63	2
64	2
65	2
66	2
67	3
68	2
69	2
70	2
71	2
72	2
73	3
74	2
75	2
76	2
77	2
78	2
79	2
80	2
81	2
82	3
83	2
84	2
85	2
86	5
87	2

n	a(n)
1	3
2	2
3	2
4	3
5	3
6	3
7	2
8	2
9	2
10	2
11	2
12	2
13	3
14	2
15	4
16	2
17	2
18	2
19	3
20	2
21	3
22	3
23	2
24	2
25	2
26	2
27	2
28	2
29	3
30	2
31	3
32	2
33	2
34	2
35	2
36	5
37	2
38	2
39	2
40	5
41	2
42	5
43	5
44	3
45	2
46	2
47	3
48	3
49	3
50	4
51	5
52	2
53	2
54	3
55	2
56	2
57	2
58	2
59	2
60	2
61	3
62	2
63	2
64	2
65	2
66	2
67	3
68	2
69	2
70	2
71	2
72	2
73	3
74	2
75	2
76	2
77	2
78	2
79	2
80	2
81	2
82	3
83	2
84	2
85	2
86	5
87	2