cp's OEIS Frontend

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.

A247558 Smallest integer x > 0 such that the number of semiprimes in the interval (x/2, x] equals n.

Table of values

n a(n)
1 4
2 6
3 10
4 15
5 25
6 26
7 35
8 38
9 39
10 57
11 58
12 62
13 65
14 86
15 87
16 91
17 94
18 95
19 121
20 122
21 123
22 134
23 142
24 143
25 145
26 146
27 159
28 161
29 169
30 202
31 203
32 205
33 206
34 209
35 214
36 215
37 217
38 218
39 219
40 221
41 262
42 265
43 278
44 299
45 301
46 302
47 303
48 305
49 309
50 326
51 327
52 329
53 335
54 341
55 346
56 361
57 362
58 365
59 382
60 386
61 393
62 394
63 395
64 398

List of values

[4, 6, 10, 15, 25, 26, 35, 38, 39, 57, 58, 62, 65, 86, 87, 91, 94, 95, 121, 122, 123, 134, 142, 143, 145, 146, 159, 161, 169, 202, 203, 205, 206, 209, 214, 215, 217, 218, 219, 221, 262, 265, 278, 299, 301, 302, 303, 305, 309, 326, 327, 329, 335, 341, 346, 361, 362, 365, 382, 386, 393, 394, 395, 398]

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

Content is available under The OEIS End-User License Agreement.