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 | 12 |
| 3 | 8 |
| 4 | 720 |
| 5 | 288 |
| 6 | 60480 |
| 7 | 17280 |
| 8 | 3628800 |
| 9 | 89600 |
| 10 | 95800320 |
| 11 | 17418240 |
| 12 | 2615348736000 |
| 13 | 402361344000 |
| 14 | 4483454976000 |
| 15 | 98402304 |
| 16 | 32011868528640000 |
| 17 | 342372925440000 |
| 18 | 51090942171709440000 |
| 19 | 5377993912811520000 |
| 20 | 33720021833328230400000 |