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) |
|---|---|
| 1 | 1 |
| 2 | 6 |
| 3 | 120 |
| 4 | 504 |
| 5 | 2 |
| 6 | 60 |
| 7 | 336 |
| 8 | 288 |
| 9 | 40320 |
| 10 | 15552 |
| 11 | 1837080 |
| 12 | 1327104 |
| 13 | 309657600 |
| 14 | 393750000 |
| 15 | 2015539200 |
| 16 | 94097687040 |
| 17 | 1366159011840 |
| 18 | 54793045278720 |
| 19 | 140587147048320 |
| 20 | 720 |
| 21 | 3024 |
| 22 | 120960 |
| 23 | 10321920 |
| 24 | 28343520 |
| 25 | 334430208 |