A322019 - cp's OEIS frontend

A322019 a(n) = A000005(n) - A014197(n), where A000005(n) gives the number of divisors of n, and A014197(n) gives the number of integers m with phi(m) = n.

n	a(n)
1	-1
2	-1
3	2
4	-1
5	2
6	0
7	2
8	-1
9	3
10	2
11	2
12	0
13	2
14	4
15	4
16	-1
17	2
18	2
19	2
20	1
21	4
22	2
23	2
24	-2
25	3
26	4
27	4
28	4
29	2
30	6
31	2
32	-1
33	4
34	4
35	4
36	1
37	2
38	4
39	4
40	-1
41	2
42	4
43	2
44	3
45	6
46	2
47	2
48	-1
49	3
50	6
51	4
52	4
53	2
54	6
55	4
56	5
57	4
58	2
59	2
60	3
61	2
62	4
63	6
64	-1
65	4
66	6
67	2
68	6
69	4
70	6
71	2
72	-5
73	2
74	4
75	6
76	6
77	4
78	6
79	2
80	0
81	5
82	2
83	2
84	6
85	4
86	4
87	4
88	2
89	2
90	12
91	4
92	3
93	4
94	4
95	4
96	-5
97	2
98	6
99	6
100	5
101	2
102	6
103	2
104	5
105	8

[-1, -1, 2, -1, 2, 0, 2, -1, 3, 2, 2, 0, 2, 4, 4, -1, 2, 2, 2, 1, 4, 2, 2, -2, 3, 4, 4, 4, 2, 6, 2, -1, 4, 4, 4, 1, 2, 4, 4, -1, 2, 4, 2, 3, 6, 2, 2, -1, 3, 6, 4, 4, 2, 6, 4, 5, 4, 2, 2, 3, 2, 4, 6, -1, 4, 6, 2, 6, 4, 6, 2, -5, 2, 4, 6, 6, 4, 6, 2, 0, 5, 2, 2, 6, 4, 4, 4, 2, 2, 12, 4, 3, 4, 4, 4, -5, 2, 6, 6, 5, 2, 6, 2, 5, 8]

cp's OEIS Frontend

A322019 a(n) = A000005(n) - A014197(n), where A000005(n) gives the number of divisors of n, and A014197(n) gives the number of integers m with phi(m) = n.

Table of values

List of values

n	a(n)
1	-1
2	-1
3	2
4	-1
5	2
6	0
7	2
8	-1
9	3
10	2
11	2
12	0
13	2
14	4
15	4
16	-1
17	2
18	2
19	2
20	1
21	4
22	2
23	2
24	-2
25	3
26	4
27	4
28	4
29	2
30	6
31	2
32	-1
33	4
34	4
35	4
36	1
37	2
38	4
39	4
40	-1
41	2
42	4
43	2
44	3
45	6
46	2
47	2
48	-1
49	3
50	6
51	4
52	4
53	2
54	6
55	4
56	5
57	4
58	2
59	2
60	3
61	2
62	4
63	6
64	-1
65	4
66	6
67	2
68	6
69	4
70	6
71	2
72	-5
73	2
74	4
75	6
76	6
77	4
78	6
79	2
80	0
81	5
82	2
83	2
84	6
85	4
86	4
87	4
88	2
89	2
90	12
91	4
92	3
93	4
94	4
95	4
96	-5
97	2
98	6
99	6
100	5
101	2
102	6
103	2
104	5
105	8

n	a(n)
1	-1
2	-1
3	2
4	-1
5	2
6	0
7	2
8	-1
9	3
10	2
11	2
12	0
13	2
14	4
15	4
16	-1
17	2
18	2
19	2
20	1
21	4
22	2
23	2
24	-2
25	3
26	4
27	4
28	4
29	2
30	6
31	2
32	-1
33	4
34	4
35	4
36	1
37	2
38	4
39	4
40	-1
41	2
42	4
43	2
44	3
45	6
46	2
47	2
48	-1
49	3
50	6
51	4
52	4
53	2
54	6
55	4
56	5
57	4
58	2
59	2
60	3
61	2
62	4
63	6
64	-1
65	4
66	6
67	2
68	6
69	4
70	6
71	2
72	-5
73	2
74	4
75	6
76	6
77	4
78	6
79	2
80	0
81	5
82	2
83	2
84	6
85	4
86	4
87	4
88	2
89	2
90	12
91	4
92	3
93	4
94	4
95	4
96	-5
97	2
98	6
99	6
100	5
101	2
102	6
103	2
104	5
105	8

n	a(n)
1	-1
2	-1
3	2
4	-1
5	2
6	0
7	2
8	-1
9	3
10	2
11	2
12	0
13	2
14	4
15	4
16	-1
17	2
18	2
19	2
20	1
21	4
22	2
23	2
24	-2
25	3
26	4
27	4
28	4
29	2
30	6
31	2
32	-1
33	4
34	4
35	4
36	1
37	2
38	4
39	4
40	-1
41	2
42	4
43	2
44	3
45	6
46	2
47	2
48	-1
49	3
50	6
51	4
52	4
53	2
54	6
55	4
56	5
57	4
58	2
59	2
60	3
61	2
62	4
63	6
64	-1
65	4
66	6
67	2
68	6
69	4
70	6
71	2
72	-5
73	2
74	4
75	6
76	6
77	4
78	6
79	2
80	0
81	5
82	2
83	2
84	6
85	4
86	4
87	4
88	2
89	2
90	12
91	4
92	3
93	4
94	4
95	4
96	-5
97	2
98	6
99	6
100	5
101	2
102	6
103	2
104	5
105	8