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 | 4920 |
| 8 | 37488 |
| 9 | 319644 |
| 10 | 3033264 |
| 11 | 31784280 |
| 12 | 364902480 |
| 13 | 4509620040 |
| 14 | 59768680032 |
| 15 | 847746532152 |