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 | 1 |
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 48 |
| 5 | 360 |
| 6 | 2880 |
| 7 | 20160 |
| 8 | 241920 |
| 9 | 3265920 |
| 10 | 47174400 |
| 11 | 678585600 |
| 12 | 12933043200 |
| 13 | 193037644800 |
| 14 | 3661488230400 |
| 15 | 74537438976000 |
| 16 | 1736591560704000 |
| 17 | 36991492521984000 |