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 | 3265920 |
| 11 | 33022080 |
| 12 | 369774720 |
| 13 | 4536362880 |
| 14 | 60451816320 |
| 15 | 869007242880 |
| 16 | 13397819541120 |
| 17 | 220448163358080 |
| 18 | 3854801333416320 |
| 19 | 67295207974942080 |
| 20 | 1248445283166184320 |
| 21 | 24512281966435294080 |
| 22 | 507579925622189454720 |