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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 720 |
| 7 | 35280 |
| 8 | 564480 |
| 9 | 5080320 |
| 10 | 31752000 |
| 11 | 153679680 |
| 12 | 614718720 |
| 13 | 2120152320 |
| 14 | 6492966480 |
| 15 | 18036018000 |
| 16 | 46172206080 |
| 17 | 110279070720 |
| 18 | 248127909120 |
| 19 | 530024705280 |
| 20 | 1081683072000 |
| 21 | 2120098821120 |
| 22 | 4008311833680 |