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 | 1 |
| 3 | 1 |
| 4 | 7 |
| 5 | 6 |
| 6 | 280 |
| 7 | 120 |
| 8 | 25335 |
| 9 | 11200 |
| 10 | 276696 |
| 11 | 362880 |
| 12 | 374838255 |
| 13 | 39916800 |
| 14 | 2414617920 |
| 15 | 11721790080 |