A086920 - cp's OEIS frontend

A086920 Smallest k such that n times concatenation of k with itself followed by a 1 is a prime, or 0 if no such number exists.

n	a(n)
1	1
2	3
3	2
4	3
5	3
6	3
7	3
8	30
9	6
10	4
11	5
12	5
13	25
14	42
15	17
16	19
17	2
18	1
19	7
20	6
21	6
22	1
23	50
24	29
25	138
26	153
27	4
28	45
29	54
30	7
31	15
32	9
33	78
34	147
35	95
36	58
37	102
38	18
39	3
40	115
41	54
42	6
43	46
44	9
45	24
46	64
47	183
48	120
49	3
50	33
51	112
52	46
53	105
54	4
55	279
56	122
57	68
58	75
59	3
60	22
61	294
62	56
63	92
64	76
65	6
66	19
67	94
68	71
69	12
70	75
71	30
72	16
73	78
74	320
75	33

[1, 3, 2, 3, 3, 3, 3, 30, 6, 4, 5, 5, 25, 42, 17, 19, 2, 1, 7, 6, 6, 1, 50, 29, 138, 153, 4, 45, 54, 7, 15, 9, 78, 147, 95, 58, 102, 18, 3, 115, 54, 6, 46, 9, 24, 64, 183, 120, 3, 33, 112, 46, 105, 4, 279, 122, 68, 75, 3, 22, 294, 56, 92, 76, 6, 19, 94, 71, 12, 75, 30, 16, 78, 320, 33]

cp's OEIS Frontend

A086920 Smallest k such that n times concatenation of k with itself followed by a 1 is a prime, or 0 if no such number exists.

Table of values

List of values

n	a(n)
1	1
2	3
3	2
4	3
5	3
6	3
7	3
8	30
9	6
10	4
11	5
12	5
13	25
14	42
15	17
16	19
17	2
18	1
19	7
20	6
21	6
22	1
23	50
24	29
25	138
26	153
27	4
28	45
29	54
30	7
31	15
32	9
33	78
34	147
35	95
36	58
37	102
38	18
39	3
40	115
41	54
42	6
43	46
44	9
45	24
46	64
47	183
48	120
49	3
50	33
51	112
52	46
53	105
54	4
55	279
56	122
57	68
58	75
59	3
60	22
61	294
62	56
63	92
64	76
65	6
66	19
67	94
68	71
69	12
70	75
71	30
72	16
73	78
74	320
75	33

n	a(n)
1	1
2	3
3	2
4	3
5	3
6	3
7	3
8	30
9	6
10	4
11	5
12	5
13	25
14	42
15	17
16	19
17	2
18	1
19	7
20	6
21	6
22	1
23	50
24	29
25	138
26	153
27	4
28	45
29	54
30	7
31	15
32	9
33	78
34	147
35	95
36	58
37	102
38	18
39	3
40	115
41	54
42	6
43	46
44	9
45	24
46	64
47	183
48	120
49	3
50	33
51	112
52	46
53	105
54	4
55	279
56	122
57	68
58	75
59	3
60	22
61	294
62	56
63	92
64	76
65	6
66	19
67	94
68	71
69	12
70	75
71	30
72	16
73	78
74	320
75	33

n	a(n)
1	1
2	3
3	2
4	3
5	3
6	3
7	3
8	30
9	6
10	4
11	5
12	5
13	25
14	42
15	17
16	19
17	2
18	1
19	7
20	6
21	6
22	1
23	50
24	29
25	138
26	153
27	4
28	45
29	54
30	7
31	15
32	9
33	78
34	147
35	95
36	58
37	102
38	18
39	3
40	115
41	54
42	6
43	46
44	9
45	24
46	64
47	183
48	120
49	3
50	33
51	112
52	46
53	105
54	4
55	279
56	122
57	68
58	75
59	3
60	22
61	294
62	56
63	92
64	76
65	6
66	19
67	94
68	71
69	12
70	75
71	30
72	16
73	78
74	320
75	33