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 | 8 |
| 3 | 40 |
| 4 | 224 |
| 5 | 1280 |
| 6 | 7168 |
| 7 | 40000 |
| 8 | 231296 |
| 9 | 1436928 |
| 10 | 9773056 |
| 11 | 72242176 |
| 12 | 563679232 |
| 13 | 4491707904 |
| 14 | 35735001088 |
| 15 | 280941652992 |
| 16 | 2178641254400 |
| 17 | 16710771339264 |
| 18 | 127402021142528 |
| 19 | 970887186407424 |
| 20 | 7436390169329664 |
| 21 | 57531833133899776 |
| 22 | 451525691751628800 |
| 23 | 3608174274928951296 |