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 | 14400 |
| 11 | 518400 |
| 12 | 18662400 |
| 13 | 457228800 |
| 14 | 11202105600 |
| 15 | 238978252800 |
| 16 | 5098202726400 |
| 17 | 103238605209600 |
| 18 | 2090581755494400 |
| 19 | 41811635109888000 |
| 20 | 836232702197760000 |
| 21 | 16864026160988160000 |