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 | 2 |
| 3 | 12 |
| 4 | 108 |
| 5 | 1280 |
| 6 | 18750 |
| 7 | 326592 |
| 8 | 6588344 |
| 9 | 150994944 |
| 10 | 3874204890 |
| 11 | 110000000000 |
| 12 | 3423740047332 |
| 13 | 115909305827328 |
| 14 | 4240251492291542 |
| 15 | 166680102383370240 |
| 16 | 7006302246093750000 |
| 17 | 313594649253062377472 |
| 18 | 14890324713954061755186 |
| 19 | 747581753430634213933056 |