A247342 - cp's OEIS frontend

A247342 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the odd part (A000265) of concatenation b_k 2^n is prime, or a(n)=0 if there is no such prime.

n	a(n)
0	1
1	2
2	1
3	1
4	1
5	1
6	4
7	3
8	2
9	1
10	3
11	1
12	1
13	6
14	1
15	1
16	1
17	3
18	1
19	15
20	29
21	5
22	1
23	2
24	3
25	6
26	1
27	6
28	20
29	6
30	3
31	50
32	3
33	22
34	8
35	5
36	5
37	1
38	84
39	8
40	7
41	36
42	3
43	6
44	7
45	20
46	6
47	6
48	8
49	1
50	6
51	3
52	2
53	38
54	1
55	5
56	3
57	2
58	5
59	16
60	1
61	12
62	13
63	7
64	1
65	4
66	16
67	5
68	32
69	1
70	6
71	13
72	4
73	150
74	7
75	29
76	17
77	9
78	12
79	34

[1, 2, 1, 1, 1, 1, 4, 3, 2, 1, 3, 1, 1, 6, 1, 1, 1, 3, 1, 15, 29, 5, 1, 2, 3, 6, 1, 6, 20, 6, 3, 50, 3, 22, 8, 5, 5, 1, 84, 8, 7, 36, 3, 6, 7, 20, 6, 6, 8, 1, 6, 3, 2, 38, 1, 5, 3, 2, 5, 16, 1, 12, 13, 7, 1, 4, 16, 5, 32, 1, 6, 13, 4, 150, 7, 29, 17, 9, 12, 34]

cp's OEIS Frontend

A247342 Let b_k=3...3 consist of k>=1 3's. Then a(n) is the smallest k such that the odd part (A000265) of concatenation b_k 2^n is prime, or a(n)=0 if there is no such prime.

Table of values

List of values

n	a(n)
0	1
1	2
2	1
3	1
4	1
5	1
6	4
7	3
8	2
9	1
10	3
11	1
12	1
13	6
14	1
15	1
16	1
17	3
18	1
19	15
20	29
21	5
22	1
23	2
24	3
25	6
26	1
27	6
28	20
29	6
30	3
31	50
32	3
33	22
34	8
35	5
36	5
37	1
38	84
39	8
40	7
41	36
42	3
43	6
44	7
45	20
46	6
47	6
48	8
49	1
50	6
51	3
52	2
53	38
54	1
55	5
56	3
57	2
58	5
59	16
60	1
61	12
62	13
63	7
64	1
65	4
66	16
67	5
68	32
69	1
70	6
71	13
72	4
73	150
74	7
75	29
76	17
77	9
78	12
79	34

n	a(n)
0	1
1	2
2	1
3	1
4	1
5	1
6	4
7	3
8	2
9	1
10	3
11	1
12	1
13	6
14	1
15	1
16	1
17	3
18	1
19	15
20	29
21	5
22	1
23	2
24	3
25	6
26	1
27	6
28	20
29	6
30	3
31	50
32	3
33	22
34	8
35	5
36	5
37	1
38	84
39	8
40	7
41	36
42	3
43	6
44	7
45	20
46	6
47	6
48	8
49	1
50	6
51	3
52	2
53	38
54	1
55	5
56	3
57	2
58	5
59	16
60	1
61	12
62	13
63	7
64	1
65	4
66	16
67	5
68	32
69	1
70	6
71	13
72	4
73	150
74	7
75	29
76	17
77	9
78	12
79	34

n	a(n)
0	1
1	2
2	1
3	1
4	1
5	1
6	4
7	3
8	2
9	1
10	3
11	1
12	1
13	6
14	1
15	1
16	1
17	3
18	1
19	15
20	29
21	5
22	1
23	2
24	3
25	6
26	1
27	6
28	20
29	6
30	3
31	50
32	3
33	22
34	8
35	5
36	5
37	1
38	84
39	8
40	7
41	36
42	3
43	6
44	7
45	20
46	6
47	6
48	8
49	1
50	6
51	3
52	2
53	38
54	1
55	5
56	3
57	2
58	5
59	16
60	1
61	12
62	13
63	7
64	1
65	4
66	16
67	5
68	32
69	1
70	6
71	13
72	4
73	150
74	7
75	29
76	17
77	9
78	12
79	34