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 | 12 |
| 2 | 690 |
| 3 | 52808 |
| 4 | 4558410 |
| 5 | 420421056 |
| 6 | 40433534960 |
| 7 | 4002511248720 |
| 8 | 404653074076602 |
| 9 | 41573640435563720 |
| 10 | 4325688482694408060 |
| 11 | 454713687334494619200 |
| 12 | 48204482093235945250800 |
| 13 | 5146506898529612988887424 |
| 14 | 552782991828545241240684480 |
| 15 | 59682974236253934536767852960 |