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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.

A340068 a(n) is the number of integers in the set {n+1,n+2, . . . ,2n} whose representation in base 2 contain exactly three digits 1’s.

Table of values

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

List of values

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

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