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) |
|---|---|
| 0 | 0 |
| 1 | 3 |
| 2 | 12 |
| 3 | 54 |
| 4 | 288 |
| 5 | 1800 |
| 6 | 12960 |
| 7 | 105840 |
| 8 | 967680 |
| 9 | 9797760 |
| 10 | 108864000 |
| 11 | 1317254400 |
| 12 | 17244057600 |
| 13 | 242853811200 |
| 14 | 3661488230400 |
| 15 | 58845346560000 |
| 16 | 1004293914624000 |
| 17 | 18140058832896000 |
| 18 | 345728180109312000 |