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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 720 |
| 7 | 12600 |
| 8 | 134400 |
| 9 | 1134000 |
| 10 | 8341200 |
| 11 | 56133000 |
| 12 | 355291200 |
| 13 | 2151864000 |
| 14 | 12614281680 |
| 15 | 72135063000 |
| 16 | 404672486400 |
| 17 | 2236228722000 |
| 18 | 12209943566160 |
| 19 | 66024457842600 |
| 20 | 354214283304000 |
| 21 | 1887999348060000 |
| 22 | 10008933180578640 |
| 23 | 52820388477271800 |
| 24 | 277680637970208000 |