A066087 - cp's OEIS frontend

A066087 a(n) = gcd(sigma(n), phi(n)) - gcd(sigma(rad(n)), phi(rad(n))); rad = A007947.

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	-1
10	0
11	0
12	2
13	0
14	0
15	0
16	0
17	0
18	1
19	0
20	0
21	0
22	0
23	0
24	2
25	-1
26	0
27	0
28	-2
29	0
30	0
31	0
32	0
33	0
34	0
35	0
36	-1
37	0
38	0
39	0
40	0
41	0
42	0
43	0
44	2
45	-2
46	0
47	0
48	2
49	1
50	-1
51	0
52	-4
53	0
54	4
55	0
56	18
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	0
67	0
68	0
69	0
70	0
71	0
72	1
73	0
74	0
75	-4
76	-2
77	0
78	0
79	0
80	0
81	-1
82	0
83	0
84	-4
85	0
86	0
87	0
88	18
89	0
90	-2
91	0
92	2
93	0
94	0
95	0
96	2
97	0
98	-3
99	8
100	-1
101	0
102	0
103	0
104	0
105	0
106	0
107	0
108	2
109	0
110	0
111	0
112	2
113	0
114	0
115	0
116	12
117	-6

[0, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 2, -1, 0, 0, -2, 0, 0, 0, 0, 0, 0, 0, -1, 0, 0, 0, 0, 0, 0, 0, 2, -2, 0, 0, 2, 1, -1, 0, -4, 0, 4, 0, 18, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, -4, -2, 0, 0, 0, 0, -1, 0, 0, -4, 0, 0, 0, 18, 0, -2, 0, 2, 0, 0, 0, 2, 0, -3, 8, -1, 0, 0, 0, 0, 0, 0, 0, 2, 0, 0, 0, 2, 0, 0, 0, 12, -6]

cp's OEIS Frontend

A066087 a(n) = gcd(sigma(n), phi(n)) - gcd(sigma(rad(n)), phi(rad(n))); rad = A007947.

Table of values

List of values

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	-1
10	0
11	0
12	2
13	0
14	0
15	0
16	0
17	0
18	1
19	0
20	0
21	0
22	0
23	0
24	2
25	-1
26	0
27	0
28	-2
29	0
30	0
31	0
32	0
33	0
34	0
35	0
36	-1
37	0
38	0
39	0
40	0
41	0
42	0
43	0
44	2
45	-2
46	0
47	0
48	2
49	1
50	-1
51	0
52	-4
53	0
54	4
55	0
56	18
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	0
67	0
68	0
69	0
70	0
71	0
72	1
73	0
74	0
75	-4
76	-2
77	0
78	0
79	0
80	0
81	-1
82	0
83	0
84	-4
85	0
86	0
87	0
88	18
89	0
90	-2
91	0
92	2
93	0
94	0
95	0
96	2
97	0
98	-3
99	8
100	-1
101	0
102	0
103	0
104	0
105	0
106	0
107	0
108	2
109	0
110	0
111	0
112	2
113	0
114	0
115	0
116	12
117	-6

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	-1
10	0
11	0
12	2
13	0
14	0
15	0
16	0
17	0
18	1
19	0
20	0
21	0
22	0
23	0
24	2
25	-1
26	0
27	0
28	-2
29	0
30	0
31	0
32	0
33	0
34	0
35	0
36	-1
37	0
38	0
39	0
40	0
41	0
42	0
43	0
44	2
45	-2
46	0
47	0
48	2
49	1
50	-1
51	0
52	-4
53	0
54	4
55	0
56	18
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	0
67	0
68	0
69	0
70	0
71	0
72	1
73	0
74	0
75	-4
76	-2
77	0
78	0
79	0
80	0
81	-1
82	0
83	0
84	-4
85	0
86	0
87	0
88	18
89	0
90	-2
91	0
92	2
93	0
94	0
95	0
96	2
97	0
98	-3
99	8
100	-1
101	0
102	0
103	0
104	0
105	0
106	0
107	0
108	2
109	0
110	0
111	0
112	2
113	0
114	0
115	0
116	12
117	-6

n	a(n)
1	0
2	0
3	0
4	0
5	0
6	0
7	0
8	0
9	-1
10	0
11	0
12	2
13	0
14	0
15	0
16	0
17	0
18	1
19	0
20	0
21	0
22	0
23	0
24	2
25	-1
26	0
27	0
28	-2
29	0
30	0
31	0
32	0
33	0
34	0
35	0
36	-1
37	0
38	0
39	0
40	0
41	0
42	0
43	0
44	2
45	-2
46	0
47	0
48	2
49	1
50	-1
51	0
52	-4
53	0
54	4
55	0
56	18
57	0
58	0
59	0
60	0
61	0
62	0
63	0
64	0
65	0
66	0
67	0
68	0
69	0
70	0
71	0
72	1
73	0
74	0
75	-4
76	-2
77	0
78	0
79	0
80	0
81	-1
82	0
83	0
84	-4
85	0
86	0
87	0
88	18
89	0
90	-2
91	0
92	2
93	0
94	0
95	0
96	2
97	0
98	-3
99	8
100	-1
101	0
102	0
103	0
104	0
105	0
106	0
107	0
108	2
109	0
110	0
111	0
112	2
113	0
114	0
115	0
116	12
117	-6