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 | 0 |
| 2 | 8 |
| 3 | 24 |
| 4 | 216 |
| 5 | 1200 |
| 6 | 8840 |
| 7 | 58800 |
| 8 | 423640 |
| 9 | 3000480 |
| 10 | 21824208 |
| 11 | 158964960 |
| 12 | 1171230984 |
| 13 | 8668531872 |
| 14 | 64574844048 |
| 15 | 483114856224 |
| 16 | 3630440899800 |
| 17 | 27379154692032 |
| 18 | 207172490054816 |
| 19 | 1572194644061184 |
| 20 | 11962847247681616 |
| 21 | 91242602561647680 |
| 22 | 697438669619791008 |