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 | 1 |
| 6 | 30 |
| 7 | 735 |
| 8 | 17920 |
| 9 | 459270 |
| 10 | 12600000 |
| 11 | 372027810 |
| 12 | 11824496640 |
| 13 | 403786706895 |
| 14 | 14772648450560 |
| 15 | 577227041015625 |
| 16 | 24013333950627840 |
| 17 | 1060372471758165020 |
| 18 | 49558656380297379840 |
| 19 | 2444960458495625410260 |
| 20 | 127008768000000000000000 |