A067934 - cp's OEIS frontend

A067934 Let rep(k) = (10^k - 1)/9 be the k-th repunit number = 11111..1111 with k 1 digits, then sequence gives values of k such that rep(k) == 1 (mod k).

n	a(n)
1	1
2	2
3	5
4	7
5	10
6	11
7	13
8	17
9	19
10	23
11	29
12	31
13	37
14	41
15	43
16	47
17	53
18	55
19	59
20	61
21	67
22	71
23	73
24	79
25	83
26	89
27	91
28	97
29	101
30	103
31	107
32	109
33	113
34	127
35	131
36	137
37	139
38	149
39	151
40	157
41	163
42	167
43	173
44	179
45	181
46	191
47	193
48	197
49	199
50	211
51	223
52	227
53	229
54	233
55	239
56	241
57	251
58	257
59	259

[1, 2, 5, 7, 10, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 55, 59, 61, 67, 71, 73, 79, 83, 89, 91, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 259]

cp's OEIS Frontend

A067934 Let rep(k) = (10^k - 1)/9 be the k-th repunit number = 11111..1111 with k 1 digits, then sequence gives values of k such that rep(k) == 1 (mod k).

Table of values

List of values

n	a(n)
1	1
2	2
3	5
4	7
5	10
6	11
7	13
8	17
9	19
10	23
11	29
12	31
13	37
14	41
15	43
16	47
17	53
18	55
19	59
20	61
21	67
22	71
23	73
24	79
25	83
26	89
27	91
28	97
29	101
30	103
31	107
32	109
33	113
34	127
35	131
36	137
37	139
38	149
39	151
40	157
41	163
42	167
43	173
44	179
45	181
46	191
47	193
48	197
49	199
50	211
51	223
52	227
53	229
54	233
55	239
56	241
57	251
58	257
59	259

n	a(n)
1	1
2	2
3	5
4	7
5	10
6	11
7	13
8	17
9	19
10	23
11	29
12	31
13	37
14	41
15	43
16	47
17	53
18	55
19	59
20	61
21	67
22	71
23	73
24	79
25	83
26	89
27	91
28	97
29	101
30	103
31	107
32	109
33	113
34	127
35	131
36	137
37	139
38	149
39	151
40	157
41	163
42	167
43	173
44	179
45	181
46	191
47	193
48	197
49	199
50	211
51	223
52	227
53	229
54	233
55	239
56	241
57	251
58	257
59	259

n	a(n)
1	1
2	2
3	5
4	7
5	10
6	11
7	13
8	17
9	19
10	23
11	29
12	31
13	37
14	41
15	43
16	47
17	53
18	55
19	59
20	61
21	67
22	71
23	73
24	79
25	83
26	89
27	91
28	97
29	101
30	103
31	107
32	109
33	113
34	127
35	131
36	137
37	139
38	149
39	151
40	157
41	163
42	167
43	173
44	179
45	181
46	191
47	193
48	197
49	199
50	211
51	223
52	227
53	229
54	233
55	239
56	241
57	251
58	257
59	259