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 | 0 |
| 1 | 4 |
| 2 | 96 |
| 3 | 4320 |
| 4 | 322560 |
| 5 | 36288000 |
| 6 | 5748019200 |
| 7 | 1220496076800 |
| 8 | 334764638208000 |
| 9 | 115242726703104000 |
| 10 | 48658040163532800000 |
| 11 | 24728016011107368960000 |
| 12 | 14890761641597746544640000 |
| 13 | 10485577989291746525184000000 |