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 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 40320 |
| 9 | 362880 |
| 10 | 40320 |
| 11 | 403200 |
| 12 | 846720 |
| 13 | 2943360 |
| 14 | 12620160 |
| 15 | 66044160 |
| 16 | 408885120 |
| 17 | 2928240000 |
| 18 | 23834805120 |
| 19 | 217441486080 |
| 20 | 47669610240 |
| 21 | 482552582400 |
| 22 | 1060444385280 |
| 23 | 4146438320640 |
| 24 | 18706642053120 |
| 25 | 101826086906880 |
| 26 | 648369805547520 |