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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 6 |
| 7 | 12 |
| 8 | 60 |
| 9 | 360 |
| 10 | 1260 |
| 11 | 10080 |
| 12 | 15120 |
| 13 | 25200 |
| 14 | 1247400 |
| 15 | 32432400 |
| 16 | 12612600 |
| 17 | 6810804000 |
| 18 | 7264857600 |
| 19 | 185253868800 |
| 20 | 1005663859200 |
| 21 | 1117404288000 |
| 22 | 4839757322400 |
| 23 | 93504111468768000 |
| 24 | 37401644587507200 |
| 25 | 160787493266400000 |
| 26 | 13023786954578400000 |