A323326 - cp's OEIS frontend

A323326 a(n) = 2*T(n) - pi(n), where T(n) (A208251) is the number of refactorable/tau numbers (A033950) <= n and pi(n) (A000720) is the number of primes <= n.

n	a(n)
1	2
2	3
3	2
4	2
5	1
6	1
7	0
8	2
9	4
10	4
11	3
12	5
13	4
14	4
15	4
16	4
17	3
18	5
19	4
20	4
21	4
22	4
23	3
24	5
25	5
26	5
27	5
28	5
29	4
30	4
31	3
32	3
33	3
34	3
35	3
36	5
37	4
38	4
39	4
40	6
41	5
42	5
43	4
44	4
45	4
46	4
47	3
48	3
49	3
50	3
51	3
52	3
53	2
54	2
55	2
56	4
57	4
58	4
59	3
60	5
61	4
62	4
63	4
64	4
65	4
66	4
67	3
68	3
69	3
70	3
71	2
72	4
73	3
74	3
75	3
76	3
77	3
78	3
79	2
80	4
81	4
82	4
83	3
84	5
85	5
86	5
87	5
88	7
89	6
90	6
91	6
92	6
93	6
94	6
95	6
96	8
97	7
98	7
99	7
100	7
101	6
102	6
103	5
104	7
105	7
106	7
107	6
108	8
109	7
110	7
111	7
112	7
113	6
114	6
115	6
116	6
117	6
118	6
119	6
120	6
121	6
122	6
123	6

[2, 3, 2, 2, 1, 1, 0, 2, 4, 4, 3, 5, 4, 4, 4, 4, 3, 5, 4, 4, 4, 4, 3, 5, 5, 5, 5, 5, 4, 4, 3, 3, 3, 3, 3, 5, 4, 4, 4, 6, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 2, 2, 2, 4, 4, 4, 3, 5, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 2, 4, 3, 3, 3, 3, 3, 3, 2, 4, 4, 4, 3, 5, 5, 5, 5, 7, 6, 6, 6, 6, 6, 6, 6, 8, 7, 7, 7, 7, 6, 6, 5, 7, 7, 7, 6, 8, 7, 7, 7, 7, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6]

cp's OEIS Frontend

A323326 a(n) = 2*T(n) - pi(n), where T(n) (A208251) is the number of refactorable/tau numbers (A033950) <= n and pi(n) (A000720) is the number of primes <= n.

Table of values

List of values

n	a(n)
1	2
2	3
3	2
4	2
5	1
6	1
7	0
8	2
9	4
10	4
11	3
12	5
13	4
14	4
15	4
16	4
17	3
18	5
19	4
20	4
21	4
22	4
23	3
24	5
25	5
26	5
27	5
28	5
29	4
30	4
31	3
32	3
33	3
34	3
35	3
36	5
37	4
38	4
39	4
40	6
41	5
42	5
43	4
44	4
45	4
46	4
47	3
48	3
49	3
50	3
51	3
52	3
53	2
54	2
55	2
56	4
57	4
58	4
59	3
60	5
61	4
62	4
63	4
64	4
65	4
66	4
67	3
68	3
69	3
70	3
71	2
72	4
73	3
74	3
75	3
76	3
77	3
78	3
79	2
80	4
81	4
82	4
83	3
84	5
85	5
86	5
87	5
88	7
89	6
90	6
91	6
92	6
93	6
94	6
95	6
96	8
97	7
98	7
99	7
100	7
101	6
102	6
103	5
104	7
105	7
106	7
107	6
108	8
109	7
110	7
111	7
112	7
113	6
114	6
115	6
116	6
117	6
118	6
119	6
120	6
121	6
122	6
123	6

n	a(n)
1	2
2	3
3	2
4	2
5	1
6	1
7	0
8	2
9	4
10	4
11	3
12	5
13	4
14	4
15	4
16	4
17	3
18	5
19	4
20	4
21	4
22	4
23	3
24	5
25	5
26	5
27	5
28	5
29	4
30	4
31	3
32	3
33	3
34	3
35	3
36	5
37	4
38	4
39	4
40	6
41	5
42	5
43	4
44	4
45	4
46	4
47	3
48	3
49	3
50	3
51	3
52	3
53	2
54	2
55	2
56	4
57	4
58	4
59	3
60	5
61	4
62	4
63	4
64	4
65	4
66	4
67	3
68	3
69	3
70	3
71	2
72	4
73	3
74	3
75	3
76	3
77	3
78	3
79	2
80	4
81	4
82	4
83	3
84	5
85	5
86	5
87	5
88	7
89	6
90	6
91	6
92	6
93	6
94	6
95	6
96	8
97	7
98	7
99	7
100	7
101	6
102	6
103	5
104	7
105	7
106	7
107	6
108	8
109	7
110	7
111	7
112	7
113	6
114	6
115	6
116	6
117	6
118	6
119	6
120	6
121	6
122	6
123	6

n	a(n)
1	2
2	3
3	2
4	2
5	1
6	1
7	0
8	2
9	4
10	4
11	3
12	5
13	4
14	4
15	4
16	4
17	3
18	5
19	4
20	4
21	4
22	4
23	3
24	5
25	5
26	5
27	5
28	5
29	4
30	4
31	3
32	3
33	3
34	3
35	3
36	5
37	4
38	4
39	4
40	6
41	5
42	5
43	4
44	4
45	4
46	4
47	3
48	3
49	3
50	3
51	3
52	3
53	2
54	2
55	2
56	4
57	4
58	4
59	3
60	5
61	4
62	4
63	4
64	4
65	4
66	4
67	3
68	3
69	3
70	3
71	2
72	4
73	3
74	3
75	3
76	3
77	3
78	3
79	2
80	4
81	4
82	4
83	3
84	5
85	5
86	5
87	5
88	7
89	6
90	6
91	6
92	6
93	6
94	6
95	6
96	8
97	7
98	7
99	7
100	7
101	6
102	6
103	5
104	7
105	7
106	7
107	6
108	8
109	7
110	7
111	7
112	7
113	6
114	6
115	6
116	6
117	6
118	6
119	6
120	6
121	6
122	6
123	6