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 | 3 |
| 3 | 12 |
| 4 | 60 |
| 5 | 120 |
| 6 | 840 |
| 7 | 2520 |
| 8 | 12600 |
| 9 | 239400 |
| 10 | 2633400 |
| 11 | 5266800 |
| 12 | 15800400 |
| 13 | 458211600 |
| 14 | 7789597200 |
| 15 | 288215096400 |
| 16 | 3746796253200 |
| 17 | 26227573772400 |
| 18 | 131137868862000 |
| 19 | 1049102950896000 |
| 20 | 24129367870608000 |
| 21 | 1906220061778032000 |
| 22 | 78155022532899312000 |
| 23 | 6955797005428038768000 |