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.
| n | a(n) |
|---|---|
| 1 | 4 |
| 2 | 8 |
| 3 | 21 |
| 4 | 64 |
| 5 | 204 |
| 6 | 682 |
| 7 | 2340 |
| 8 | 8192 |
| 9 | 29127 |
| 10 | 104857 |
| 11 | 381300 |
| 12 | 1398101 |
| 13 | 5162220 |
| 14 | 19173961 |
| 15 | 71582788 |
| 16 | 268435456 |
| 17 | 1010580540 |
| 18 | 3817748707 |
| 19 | 14467258260 |
| 20 | 54975581388 |
| 21 | 209430786243 |
| 22 | 799644820200 |
| 23 | 3059510616420 |
| 24 | 11728124029610 |