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) |
|---|---|
| 6 | 0 |
| 7 | 80 |
| 8 | 1526 |
| 9 | 34160 |
| 10 | 576060 |
| 11 | 8762880 |
| 12 | 123760560 |
| 13 | 1602344832 |
| 14 | 21025461600 |
| 15 | 264121228800 |
| 16 | 3365570435040 |
| 17 | 42633973724160 |
| 18 | 535972460752320 |
| 19 | 7005009151595520 |
| 20 | 88526770797830400 |
| 21 | 1212423433054986240 |
| 22 | 15530632515845568000 |
| 23 | 223695310100356300800 |
| 24 | 2930160761881213132800 |