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 | 2 |
| 3 | 14 |
| 4 | 336 |
| 5 | 25836 |
| 6 | 6251504 |
| 7 | 4838830976 |
| 8 | 12344615283200 |
| 9 | 106978340796778976 |
| 10 | 3229124399759665954432 |
| 11 | 346176173916459184212747520 |
| 12 | 133788163509847808639178273046528 |