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 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 8 |
| 4 | 34 |
| 5 | 156 |
| 6 | 924 |
| 7 | 6144 |
| 8 | 48096 |
| 9 | 420480 |
| 10 | 4134240 |
| 11 | 44720640 |
| 12 | 530444160 |
| 13 | 6824805120 |
| 14 | 94787884800 |
| 15 | 1412038656000 |
| 16 | 22464536371200 |
| 17 | 380017225728000 |
| 18 | 6811416338227200 |
| 19 | 128936055177216000 |
| 20 | 2570286167543808000 |
| 21 | 53818546503794688000 |
| 22 | 1180914445357903872000 |