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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5760 |
| 8 | 51840 |
| 9 | 518400 |
| 10 | 5702400 |
| 11 | 68428800 |
| 12 | 889574400 |
| 13 | 12454041600 |
| 14 | 186810624000 |
| 15 | 2988969984000 |
| 16 | 50812489728000 |
| 17 | 914624815104000 |
| 18 | 17377871486976000 |
| 19 | 347557429739520000 |
| 20 | 7298706024529920000 |
| 21 | 160571532539658240000 |
| 22 | 3693145248412139520000 |