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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 8 |
| 6 | 100 |
| 7 | 720 |
| 8 | 5040 |
| 9 | 36736 |
| 10 | 268800 |
| 11 | 2073600 |
| 12 | 17186400 |
| 13 | 147502080 |
| 14 | 1331616000 |
| 15 | 13047091200 |
| 16 | 110053944000 |
| 17 | 1011903692800 |
| 18 | 9874978713600 |
| 19 | 106953080832000 |
| 20 | 1086116967936000 |
| 21 | 12275238666240000 |
| 22 | 144074916311040000 |
| 23 | 1890064025321472000 |