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.

A078972 Brilliant numbers: semiprimes (products of two primes, A001358) whose prime factors have the same number of decimal digits.

Table of values

n a(n)
1 4
2 6
3 9
4 10
5 14
6 15
7 21
8 25
9 35
10 49
11 121
12 143
13 169
14 187
15 209
16 221
17 247
18 253
19 289
20 299
21 319
22 323
23 341
24 361
25 377
26 391
27 403
28 407
29 437
30 451
31 473
32 481
33 493
34 517
35 527
36 529
37 533
38 551
39 559
40 583
41 589
42 611
43 629
44 649
45 667
46 671
47 689
48 697
49 703
50 713
51 731
52 737
53 767
54 779
55 781

List of values

[4, 6, 9, 10, 14, 15, 21, 25, 35, 49, 121, 143, 169, 187, 209, 221, 247, 253, 289, 299, 319, 323, 341, 361, 377, 391, 403, 407, 437, 451, 473, 481, 493, 517, 527, 529, 533, 551, 559, 583, 589, 611, 629, 649, 667, 671, 689, 697, 703, 713, 731, 737, 767, 779, 781]

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

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