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 | 0 |
| 2 | 0 |
| 3 | 6 |
| 4 | 32 |
| 5 | 400 |
| 6 | 2304 |
| 7 | 35280 |
| 8 | 322560 |
| 9 | 3888000 |
| 10 | 48384000 |
| 11 | 731808000 |
| 12 | 9858723840 |
| 13 | 161902540800 |
| 14 | 2628760780800 |
| 15 | 43181994240000 |
| 16 | 876764528640000 |
| 17 | 16124496740352000 |
| 18 | 358721232629760000 |
| 19 | 6933770723303424000 |
| 20 | 168738115888742400000 |
| 21 | 3644128675321085952000 |
| 22 | 94201965756599500800000 |