A057951 - cp's OEIS frontend

A057951 Number of prime factors of 10^n - 1 (counted with multiplicity).

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

[2, 3, 4, 4, 4, 7, 4, 6, 6, 6, 4, 9, 5, 6, 8, 8, 4, 11, 3, 9, 9, 9, 3, 12, 7, 8, 9, 10, 7, 15, 5, 13, 8, 8, 9, 14, 5, 5, 8, 13, 6, 17, 6, 13, 12, 8, 4, 15, 6, 12, 10, 11, 6, 16, 10, 14, 8, 10, 4, 22, 9, 7, 16, 17, 9, 17, 5, 12, 8, 14, 4, 20, 5, 9, 14, 8, 10, 18]

cp's OEIS Frontend

A057951 Number of prime factors of 10^n - 1 (counted with multiplicity).

Table of values

List of values

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

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

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