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 | 0 |
| 2 | 9 |
| 3 | 1772 |
| 4 | 662544 |
| 5 | 458284375 |
| 6 | 543682781641 |
| 7 | 1033215730131200 |
| 8 | 2972173255049281536 |
| 9 | 12354182867688591966525 |
| 10 | 71417932095699615712890625 |
| 11 | 556289577698910589026958125056 |
| 12 | 5685963330436142993425055664640000 |
| 13 | 74579993174727714813743424870936891459 |