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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 840 |
| 7 | 6720 |
| 8 | 60480 |
| 9 | 665280 |
| 10 | 8648640 |
| 11 | 138378240 |
| 12 | 2352430080 |
| 13 | 44696171520 |
| 14 | 1028011944960 |
| 15 | 25700298624000 |
| 16 | 693908062848000 |
| 17 | 20123333822592000 |
| 18 | 623823348500352000 |
| 19 | 19962347152011264000 |
| 20 | 738606844624416768000 |
| 21 | 30282880629601087488000 |
| 22 | 1302163867072846761984000 |