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 | 2 |
| 2 | 15 |
| 3 | 280 |
| 4 | 9945 |
| 5 | 576576 |
| 6 | 49579075 |
| 7 | 5925744000 |
| 8 | 939536222625 |
| 9 | 190787784140800 |
| 10 | 48279601331512551 |
| 11 | 14894665739501184000 |
| 12 | 5502449072258318805625 |
| 13 | 2397950328737212204032000 |