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 | 4 |
| 3 | 24 |
| 4 | 144 |
| 5 | 960 |
| 6 | 7200 |
| 7 | 60480 |
| 8 | 564480 |
| 9 | 5806080 |
| 10 | 65318400 |
| 11 | 798336000 |
| 12 | 10538035200 |
| 13 | 149448499200 |
| 14 | 2266635571200 |
| 15 | 36614882304000 |
| 16 | 627683696640000 |
| 17 | 11381997699072000 |
| 18 | 217680705994752000 |