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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 4 |
| 3 | 24 |
| 4 | 96 |
| 5 | 320 |
| 6 | 960 |
| 7 | 2688 |
| 8 | 7168 |
| 9 | 18432 |
| 10 | 46080 |
| 11 | 112640 |
| 12 | 270336 |
| 13 | 638976 |
| 14 | 1490944 |
| 15 | 3440640 |
| 16 | 7864320 |
| 17 | 17825792 |
| 18 | 40108032 |
| 19 | 89653248 |
| 20 | 199229440 |
| 21 | 440401920 |
| 22 | 968884224 |
| 23 | 2122317824 |
| 24 | 4630511616 |
| 25 | 10066329600 |
| 26 | 21810380800 |
| 27 | 47110422528 |