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 | 4 |
| 2 | 3 |
| 3 | 48 |
| 4 | 40 |
| 5 | 1440 |
| 6 | 1260 |
| 7 | 8960 |
| 8 | 72576 |
| 9 | 7257600 |
| 10 | 6652800 |
| 11 | 958003200 |
| 12 | 889574400 |
| 13 | 11623772160 |
| 14 | 163459296000 |
| 15 | 41845579776000 |
| 16 | 39520825344000 |
| 17 | 12804747411456000 |
| 18 | 12164510040883200 |
| 19 | 231704953159680000 |
| 20 | 4644631106519040000 |