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 | 0 |
| 10 | 3628800 |
| 11 | 439084800 |
| 12 | 15807052800 |
| 13 | 296821324800 |
| 14 | 3636061228800 |
| 15 | 32724551059200 |
| 16 | 232707918643200 |
| 17 | 1372501805875200 |
| 18 | 6948290392243200 |
| 19 | 30967071995059200 |
| 20 | 123868287980236800 |