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.

A029490 Numbers k that divide the (left) concatenation of all numbers <= k written in base 21 (most significant digit on left).

Table of values

n a(n)
1 1
2 5
3 25
4 43
5 55
6 128
7 275
8 1280
9 2816
10 5888
11 6400
12 12800
13 28160
14 33413
15 37376
16 129919
17 140800
18 286025
19 352000
20 990845
21 1050880
22 1773725
23 2848000
24 3581033
25 4343680
26 4428160
27 5624960
28 6732160
29 7553920
30 8497280
31 9249995
32 9872000
33 10938752
34 11426176
35 14558575
36 14569600
37 15368320
38 18998705
39 19312000
40 21362275
41 24208000
42 24934855
43 27632000
44 32432000
45 37022605
46 43193216
47 51382265
48 53717375
49 81016375

List of values

[1, 5, 25, 43, 55, 128, 275, 1280, 2816, 5888, 6400, 12800, 28160, 33413, 37376, 129919, 140800, 286025, 352000, 990845, 1050880, 1773725, 2848000, 3581033, 4343680, 4428160, 5624960, 6732160, 7553920, 8497280, 9249995, 9872000, 10938752, 11426176, 14558575, 14569600, 15368320, 18998705, 19312000, 21362275, 24208000, 24934855, 27632000, 32432000, 37022605, 43193216, 51382265, 53717375, 81016375]

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

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