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 | 0 |
| 3 | 2 |
| 4 | 24 |
| 5 | 544 |
| 6 | 22320 |
| 7 | 1677488 |
| 8 | 236522496 |
| 9 | 64026088576 |
| 10 | 33832910196480 |
| 11 | 35262092417856512 |
| 12 | 72926863133112198144 |
| 13 | 300318571786159783496704 |
| 14 | 2467430973323656141183549440 |
| 15 | 40490606137578335674252914280448 |