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 | 504 |
| 3 | 19656 |
| 4 | 262080 |
| 5 | 1953000 |
| 6 | 10077480 |
| 7 | 40353264 |
| 8 | 134217216 |
| 9 | 387419760 |
| 10 | 999999000 |
| 11 | 2357946360 |
| 12 | 5159778624 |
| 13 | 10604497176 |
| 14 | 20661044040 |
| 15 | 38443356000 |
| 16 | 68719472640 |
| 17 | 118587871584 |
| 18 | 198359284536 |
| 19 | 322687690920 |
| 20 | 511999992000 |
| 21 | 794280037320 |
| 22 | 1207269207144 |