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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A209628 Number of squarefree numbers < n that are not prime.

Table of values

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

List of values

[1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 5, 5, 5, 5, 5, 5, 6, 7, 7, 7, 7, 8, 8, 8, 8, 9, 9, 9, 10, 11, 12, 12, 12, 13, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 19, 20, 20, 20, 20, 21, 21, 21, 22, 23, 23, 23, 24, 25, 25, 25, 25, 26]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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