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 | 9 |
| 2 | 162 |
| 3 | 4374 |
| 4 | 157464 |
| 5 | 7085880 |
| 6 | 382637520 |
| 7 | 24106163760 |
| 8 | 1735643790720 |
| 9 | 140587147048320 |
| 10 | 12652843234348800 |
| 11 | 1252631480200531200 |
| 12 | 135284199861657369600 |
| 13 | 15828251383813912243200 |
| 14 | 1994359674360552942643200 |
| 15 | 269238556038674647256832000 |