A074795 - cp's OEIS frontend

A074795 Number of numbers k <= n such that tau(k) == 0 (mod 3) where tau(k) = A000005(k) is the number of divisors of k.

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

[0, 0, 0, 1, 1, 1, 1, 1, 2, 2, 2, 3, 3, 3, 3, 3, 3, 4, 4, 5, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 10, 11, 11, 11, 11, 12, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 19, 20, 20, 20, 20, 20, 20, 20, 20, 21]

cp's OEIS Frontend

A074795 Number of numbers k <= n such that tau(k) == 0 (mod 3) where tau(k) = A000005(k) is the number of divisors of k.

Table of values

List of values

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

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

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