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 | 0 |
| 7 | 0 |
| 8 | 0 |
| 9 | 9072 |
| 10 | 90720 |
| 11 | 498960 |
| 12 | 25945920 |
| 13 | 321080760 |
| 14 | 2460970512 |
| 15 | 14552417880 |
| 16 | 115251776640 |
| 17 | 4603779180000 |
| 18 | 72193873752000 |
| 19 | 681167139805152 |
| 20 | 16976210865344640 |
| 21 | 304992335584165320 |
| 22 | 4548189212204243760 |