A247341 - cp's OEIS frontend

A247341 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the concatenation 2^n b_k is prime, or a(n)=0 if there is no such prime.

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	4
6	1
7	1
8	2
9	3
10	1
11	1
12	4
13	4
14	6
15	30
16	3
17	1
18	6
19	1
20	32
21	3
22	3
23	2
24	22
25	1
26	6
27	1
28	2
29	14
30	7
31	1
32	10
33	1
34	2
35	6
36	3
37	4
38	2
39	5
40	2
41	6
42	1
43	1
44	37
45	53
46	53
47	13
48	64
49	1
50	67
51	1
52	45
53	29
54	17
55	12
56	14
57	1
58	2
59	5
60	15
61	36
62	10
63	7
64	1
65	1
66	81
67	4
68	18
69	5
70	55
71	8
72	33
73	19
74	8
75	6
76	2
77	11

[1, 1, 1, 1, 1, 4, 1, 1, 2, 3, 1, 1, 4, 4, 6, 30, 3, 1, 6, 1, 32, 3, 3, 2, 22, 1, 6, 1, 2, 14, 7, 1, 10, 1, 2, 6, 3, 4, 2, 5, 2, 6, 1, 1, 37, 53, 53, 13, 64, 1, 67, 1, 45, 29, 17, 12, 14, 1, 2, 5, 15, 36, 10, 7, 1, 1, 81, 4, 18, 5, 55, 8, 33, 19, 8, 6, 2, 11]

cp's OEIS Frontend

A247341 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the concatenation 2^n b_k is prime, or a(n)=0 if there is no such prime.

Table of values

List of values

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	4
6	1
7	1
8	2
9	3
10	1
11	1
12	4
13	4
14	6
15	30
16	3
17	1
18	6
19	1
20	32
21	3
22	3
23	2
24	22
25	1
26	6
27	1
28	2
29	14
30	7
31	1
32	10
33	1
34	2
35	6
36	3
37	4
38	2
39	5
40	2
41	6
42	1
43	1
44	37
45	53
46	53
47	13
48	64
49	1
50	67
51	1
52	45
53	29
54	17
55	12
56	14
57	1
58	2
59	5
60	15
61	36
62	10
63	7
64	1
65	1
66	81
67	4
68	18
69	5
70	55
71	8
72	33
73	19
74	8
75	6
76	2
77	11

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	4
6	1
7	1
8	2
9	3
10	1
11	1
12	4
13	4
14	6
15	30
16	3
17	1
18	6
19	1
20	32
21	3
22	3
23	2
24	22
25	1
26	6
27	1
28	2
29	14
30	7
31	1
32	10
33	1
34	2
35	6
36	3
37	4
38	2
39	5
40	2
41	6
42	1
43	1
44	37
45	53
46	53
47	13
48	64
49	1
50	67
51	1
52	45
53	29
54	17
55	12
56	14
57	1
58	2
59	5
60	15
61	36
62	10
63	7
64	1
65	1
66	81
67	4
68	18
69	5
70	55
71	8
72	33
73	19
74	8
75	6
76	2
77	11

n	a(n)
0	1
1	1
2	1
3	1
4	1
5	4
6	1
7	1
8	2
9	3
10	1
11	1
12	4
13	4
14	6
15	30
16	3
17	1
18	6
19	1
20	32
21	3
22	3
23	2
24	22
25	1
26	6
27	1
28	2
29	14
30	7
31	1
32	10
33	1
34	2
35	6
36	3
37	4
38	2
39	5
40	2
41	6
42	1
43	1
44	37
45	53
46	53
47	13
48	64
49	1
50	67
51	1
52	45
53	29
54	17
55	12
56	14
57	1
58	2
59	5
60	15
61	36
62	10
63	7
64	1
65	1
66	81
67	4
68	18
69	5
70	55
71	8
72	33
73	19
74	8
75	6
76	2
77	11