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) |
|---|---|
| 1 | 0 |
| 2 | 255 |
| 3 | 6560 |
| 4 | 65535 |
| 5 | 390624 |
| 6 | 1679615 |
| 7 | 5764800 |
| 8 | 16777215 |
| 9 | 43046720 |
| 10 | 99999999 |
| 11 | 214358880 |
| 12 | 429981695 |
| 13 | 815730720 |
| 14 | 1475789055 |
| 15 | 2562890624 |
| 16 | 4294967295 |
| 17 | 6975757440 |
| 18 | 11019960575 |
| 19 | 16983563040 |
| 20 | 25599999999 |
| 21 | 37822859360 |
| 22 | 54875873535 |
| 23 | 78310985280 |
| 24 | 110075314175 |