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 | 1 |
| 2 | 12 |
| 3 | 270 |
| 4 | 8960 |
| 5 | 393750 |
| 6 | 21555072 |
| 7 | 1413199788 |
| 8 | 107961384960 |
| 9 | 9418192087590 |
| 10 | 923780000000000 |
| 11 | 100633991211229476 |
| 12 | 12055263261877075968 |
| 13 | 1575041416811693275900 |
| 14 | 222887966509090352332800 |
| 15 | 33962507149515380859375000 |
| 16 | 5543988061027763016035205120 |