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 | 720 |
| 7 | 5040 |
| 8 | 5048 |
| 9 | 5112 |
| 10 | 5760 |
| 11 | 12960 |
| 12 | 100080 |
| 13 | 1240560 |
| 14 | 17302320 |
| 15 | 17302335 |
| 16 | 17302560 |
| 17 | 17306400 |
| 18 | 17375760 |
| 19 | 18697680 |
| 20 | 45209520 |
| 21 | 603353520 |
| 22 | 603353542 |
| 23 | 603354026 |
| 24 | 603365664 |
| 25 | 603657120 |
| 26 | 611247120 |
| 27 | 816480720 |
| 28 | 6570915120 |
| 29 | 6570915149 |
| 30 | 6570915990 |