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 | 0 |
| 2 | 1 |
| 3 | 24 |
| 4 | 978 |
| 5 | 63540 |
| 6 | 6075900 |
| 7 | 805351680 |
| 8 | 141497266680 |
| 9 | 31843424440800 |
| 10 | 8934902572138200 |
| 11 | 3058578720594936000 |
| 12 | 1254725049041097480000 |
| 13 | 607696683874925162918400 |
| 14 | 343106914496426524661817600 |
| 15 | 223382333871697909676511744000 |
| 16 | 166127588708309626930142410800000 |