A054571 - cp's OEIS frontend

A054571 a(n) = phi(n - phi(n)), a(1) = 0.

n	a(n)
1	0
2	1
3	1
4	1
5	1
6	2
7	1
8	2
9	2
10	2
11	1
12	4
13	1
14	4
15	6
16	4
17	1
18	4
19	1
20	4
21	6
22	4
23	1
24	8
25	4
26	6
27	6
28	8
29	1
30	10
31	1
32	8
33	12
34	6
35	10
36	8
37	1
38	8
39	8
40	8
41	1
42	8
43	1
44	8
45	12
46	8
47	1
48	16
49	6
50	8
51	18
52	12
53	1
54	12
55	8
56	16
57	12
58	8
59	1
60	20
61	1
62	16
63	18
64	16
65	16
66	22
67	1
68	12
69	20
70	22
71	1
72	16
73	1
74	18
75	24
76	16
77	16
78	18
79	1
80	16
81	18

[0, 1, 1, 1, 1, 2, 1, 2, 2, 2, 1, 4, 1, 4, 6, 4, 1, 4, 1, 4, 6, 4, 1, 8, 4, 6, 6, 8, 1, 10, 1, 8, 12, 6, 10, 8, 1, 8, 8, 8, 1, 8, 1, 8, 12, 8, 1, 16, 6, 8, 18, 12, 1, 12, 8, 16, 12, 8, 1, 20, 1, 16, 18, 16, 16, 22, 1, 12, 20, 22, 1, 16, 1, 18, 24, 16, 16, 18, 1, 16, 18]

cp's OEIS Frontend

A054571 a(n) = phi(n - phi(n)), a(1) = 0.

Table of values

List of values

n	a(n)
1	0
2	1
3	1
4	1
5	1
6	2
7	1
8	2
9	2
10	2
11	1
12	4
13	1
14	4
15	6
16	4
17	1
18	4
19	1
20	4
21	6
22	4
23	1
24	8
25	4
26	6
27	6
28	8
29	1
30	10
31	1
32	8
33	12
34	6
35	10
36	8
37	1
38	8
39	8
40	8
41	1
42	8
43	1
44	8
45	12
46	8
47	1
48	16
49	6
50	8
51	18
52	12
53	1
54	12
55	8
56	16
57	12
58	8
59	1
60	20
61	1
62	16
63	18
64	16
65	16
66	22
67	1
68	12
69	20
70	22
71	1
72	16
73	1
74	18
75	24
76	16
77	16
78	18
79	1
80	16
81	18

n	a(n)
1	0
2	1
3	1
4	1
5	1
6	2
7	1
8	2
9	2
10	2
11	1
12	4
13	1
14	4
15	6
16	4
17	1
18	4
19	1
20	4
21	6
22	4
23	1
24	8
25	4
26	6
27	6
28	8
29	1
30	10
31	1
32	8
33	12
34	6
35	10
36	8
37	1
38	8
39	8
40	8
41	1
42	8
43	1
44	8
45	12
46	8
47	1
48	16
49	6
50	8
51	18
52	12
53	1
54	12
55	8
56	16
57	12
58	8
59	1
60	20
61	1
62	16
63	18
64	16
65	16
66	22
67	1
68	12
69	20
70	22
71	1
72	16
73	1
74	18
75	24
76	16
77	16
78	18
79	1
80	16
81	18

n	a(n)
1	0
2	1
3	1
4	1
5	1
6	2
7	1
8	2
9	2
10	2
11	1
12	4
13	1
14	4
15	6
16	4
17	1
18	4
19	1
20	4
21	6
22	4
23	1
24	8
25	4
26	6
27	6
28	8
29	1
30	10
31	1
32	8
33	12
34	6
35	10
36	8
37	1
38	8
39	8
40	8
41	1
42	8
43	1
44	8
45	12
46	8
47	1
48	16
49	6
50	8
51	18
52	12
53	1
54	12
55	8
56	16
57	12
58	8
59	1
60	20
61	1
62	16
63	18
64	16
65	16
66	22
67	1
68	12
69	20
70	22
71	1
72	16
73	1
74	18
75	24
76	16
77	16
78	18
79	1
80	16
81	18