A070777 - cp's OEIS frontend

A070777 a(1) = 1; a(n) = (largest prime factor of n) - 1.

n	a(n)
1	1
2	1
3	2
4	1
5	4
6	2
7	6
8	1
9	2
10	4
11	10
12	2
13	12
14	6
15	4
16	1
17	16
18	2
19	18
20	4
21	6
22	10
23	22
24	2
25	4
26	12
27	2
28	6
29	28
30	4
31	30
32	1
33	10
34	16
35	6
36	2
37	36
38	18
39	12
40	4
41	40
42	6
43	42
44	10
45	4
46	22
47	46
48	2
49	6
50	4
51	16
52	12
53	52
54	2
55	10
56	6
57	18
58	28
59	58
60	4
61	60
62	30
63	6
64	1
65	12
66	10
67	66
68	16
69	22
70	6
71	70
72	2
73	72
74	36
75	4
76	18
77	10
78	12
79	78
80	4
81	2
82	40
83	82
84	6

[1, 1, 2, 1, 4, 2, 6, 1, 2, 4, 10, 2, 12, 6, 4, 1, 16, 2, 18, 4, 6, 10, 22, 2, 4, 12, 2, 6, 28, 4, 30, 1, 10, 16, 6, 2, 36, 18, 12, 4, 40, 6, 42, 10, 4, 22, 46, 2, 6, 4, 16, 12, 52, 2, 10, 6, 18, 28, 58, 4, 60, 30, 6, 1, 12, 10, 66, 16, 22, 6, 70, 2, 72, 36, 4, 18, 10, 12, 78, 4, 2, 40, 82, 6]

cp's OEIS Frontend

A070777 a(1) = 1; a(n) = (largest prime factor of n) - 1.

Table of values

List of values

n	a(n)
1	1
2	1
3	2
4	1
5	4
6	2
7	6
8	1
9	2
10	4
11	10
12	2
13	12
14	6
15	4
16	1
17	16
18	2
19	18
20	4
21	6
22	10
23	22
24	2
25	4
26	12
27	2
28	6
29	28
30	4
31	30
32	1
33	10
34	16
35	6
36	2
37	36
38	18
39	12
40	4
41	40
42	6
43	42
44	10
45	4
46	22
47	46
48	2
49	6
50	4
51	16
52	12
53	52
54	2
55	10
56	6
57	18
58	28
59	58
60	4
61	60
62	30
63	6
64	1
65	12
66	10
67	66
68	16
69	22
70	6
71	70
72	2
73	72
74	36
75	4
76	18
77	10
78	12
79	78
80	4
81	2
82	40
83	82
84	6

n	a(n)
1	1
2	1
3	2
4	1
5	4
6	2
7	6
8	1
9	2
10	4
11	10
12	2
13	12
14	6
15	4
16	1
17	16
18	2
19	18
20	4
21	6
22	10
23	22
24	2
25	4
26	12
27	2
28	6
29	28
30	4
31	30
32	1
33	10
34	16
35	6
36	2
37	36
38	18
39	12
40	4
41	40
42	6
43	42
44	10
45	4
46	22
47	46
48	2
49	6
50	4
51	16
52	12
53	52
54	2
55	10
56	6
57	18
58	28
59	58
60	4
61	60
62	30
63	6
64	1
65	12
66	10
67	66
68	16
69	22
70	6
71	70
72	2
73	72
74	36
75	4
76	18
77	10
78	12
79	78
80	4
81	2
82	40
83	82
84	6

n	a(n)
1	1
2	1
3	2
4	1
5	4
6	2
7	6
8	1
9	2
10	4
11	10
12	2
13	12
14	6
15	4
16	1
17	16
18	2
19	18
20	4
21	6
22	10
23	22
24	2
25	4
26	12
27	2
28	6
29	28
30	4
31	30
32	1
33	10
34	16
35	6
36	2
37	36
38	18
39	12
40	4
41	40
42	6
43	42
44	10
45	4
46	22
47	46
48	2
49	6
50	4
51	16
52	12
53	52
54	2
55	10
56	6
57	18
58	28
59	58
60	4
61	60
62	30
63	6
64	1
65	12
66	10
67	66
68	16
69	22
70	6
71	70
72	2
73	72
74	36
75	4
76	18
77	10
78	12
79	78
80	4
81	2
82	40
83	82
84	6