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 | 18 |
| 2 | 252 |
| 3 | 2520 |
| 4 | 22320 |
| 5 | 187488 |
| 6 | 1536192 |
| 7 | 12435840 |
| 8 | 100074240 |
| 9 | 802948608 |
| 10 | 6433016832 |
| 11 | 51501864960 |
| 12 | 412165877760 |
| 13 | 3297930928128 |
| 14 | 26385863196672 |
| 15 | 211096568954880 |
| 16 | 1688811205754880 |
| 17 | 13510644263682048 |