A094051 - cp's OEIS frontend

A094051 a(n) = phi(phi(p))/2 where p = prime(n).

n	a(n)
3	1
4	1
5	2
6	2
7	4
8	3
9	5
10	6
11	4
12	6
13	8
14	6
15	11
16	12
17	14
18	8
19	10
20	12
21	12
22	12
23	20
24	20
25	16
26	20
27	16
28	26
29	18
30	24
31	18
32	24
33	32
34	22
35	36
36	20
37	24
38	27
39	41
40	42
41	44
42	24
43	36
44	32
45	42
46	30
47	24
48	36
49	56
50	36
51	56
52	48
53	32
54	50
55	64
56	65
57	66
58	36
59	44
60	48
61	46
62	72
63	48
64	60
65	48
66	78
67	40
68	48
69	86
70	56
71	80
72	89
73	60
74	60
75	54
76	95
77	96
78	60

[1, 1, 2, 2, 4, 3, 5, 6, 4, 6, 8, 6, 11, 12, 14, 8, 10, 12, 12, 12, 20, 20, 16, 20, 16, 26, 18, 24, 18, 24, 32, 22, 36, 20, 24, 27, 41, 42, 44, 24, 36, 32, 42, 30, 24, 36, 56, 36, 56, 48, 32, 50, 64, 65, 66, 36, 44, 48, 46, 72, 48, 60, 48, 78, 40, 48, 86, 56, 80, 89, 60, 60, 54, 95, 96, 60]

cp's OEIS Frontend

A094051 a(n) = phi(phi(p))/2 where p = prime(n).

Table of values

List of values

n	a(n)
3	1
4	1
5	2
6	2
7	4
8	3
9	5
10	6
11	4
12	6
13	8
14	6
15	11
16	12
17	14
18	8
19	10
20	12
21	12
22	12
23	20
24	20
25	16
26	20
27	16
28	26
29	18
30	24
31	18
32	24
33	32
34	22
35	36
36	20
37	24
38	27
39	41
40	42
41	44
42	24
43	36
44	32
45	42
46	30
47	24
48	36
49	56
50	36
51	56
52	48
53	32
54	50
55	64
56	65
57	66
58	36
59	44
60	48
61	46
62	72
63	48
64	60
65	48
66	78
67	40
68	48
69	86
70	56
71	80
72	89
73	60
74	60
75	54
76	95
77	96
78	60

n	a(n)
3	1
4	1
5	2
6	2
7	4
8	3
9	5
10	6
11	4
12	6
13	8
14	6
15	11
16	12
17	14
18	8
19	10
20	12
21	12
22	12
23	20
24	20
25	16
26	20
27	16
28	26
29	18
30	24
31	18
32	24
33	32
34	22
35	36
36	20
37	24
38	27
39	41
40	42
41	44
42	24
43	36
44	32
45	42
46	30
47	24
48	36
49	56
50	36
51	56
52	48
53	32
54	50
55	64
56	65
57	66
58	36
59	44
60	48
61	46
62	72
63	48
64	60
65	48
66	78
67	40
68	48
69	86
70	56
71	80
72	89
73	60
74	60
75	54
76	95
77	96
78	60

n	a(n)
3	1
4	1
5	2
6	2
7	4
8	3
9	5
10	6
11	4
12	6
13	8
14	6
15	11
16	12
17	14
18	8
19	10
20	12
21	12
22	12
23	20
24	20
25	16
26	20
27	16
28	26
29	18
30	24
31	18
32	24
33	32
34	22
35	36
36	20
37	24
38	27
39	41
40	42
41	44
42	24
43	36
44	32
45	42
46	30
47	24
48	36
49	56
50	36
51	56
52	48
53	32
54	50
55	64
56	65
57	66
58	36
59	44
60	48
61	46
62	72
63	48
64	60
65	48
66	78
67	40
68	48
69	86
70	56
71	80
72	89
73	60
74	60
75	54
76	95
77	96
78	60