A384195 - cp's OEIS frontend

A384195 a(n) = tau(n+1) - tau(n-1), where tau(n) = A000005(n), the number of divisors of n.

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

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

cp's OEIS Frontend

A384195 a(n) = tau(n+1) - tau(n-1), where tau(n) = A000005(n), the number of divisors of n.

Table of values

List of values

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

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

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