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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 0 |
| 8 | 5040 |
| 9 | 45360 |
| 10 | 453600 |
| 11 | 3326400 |
| 12 | 39916800 |
| 13 | 363242880 |
| 14 | 3874590720 |
| 15 | 34767532800 |
| 16 | 567177811200 |
| 17 | 6897521030400 |
| 18 | 98241008785920 |
| 19 | 1138935652807680 |
| 20 | 18952720774041600 |
| 21 | 258251731634534400 |