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 | 8 |
| 3 | 42 |
| 4 | 456 |
| 5 | 4800 |
| 6 | 69840 |
| 7 | 1093680 |
| 8 | 20482560 |
| 9 | 420577920 |
| 10 | 9736070400 |
| 11 | 245887488000 |
| 12 | 6806133734400 |
| 13 | 203555082931200 |
| 14 | 6565920180019200 |
| 15 | 226728504946944000 |
| 16 | 8355118608764928000 |
| 17 | 327047476385710080000 |