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 | 20 |
| 2 | 224 |
| 3 | 1920 |
| 4 | 14080 |
| 5 | 93184 |
| 6 | 573440 |
| 7 | 3342336 |
| 8 | 18677760 |
| 9 | 100925440 |
| 10 | 530579456 |
| 11 | 2726297600 |
| 12 | 13740539904 |
| 13 | 68115496960 |
| 14 | 332859965440 |
| 15 | 1606317768704 |
| 16 | 7666516623360 |
| 17 | 36232344109056 |
| 18 | 169737107537920 |
| 19 | 788899592929280 |