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 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 720 |
| 7 | 12600 |
| 8 | 168000 |
| 9 | 2116800 |
| 10 | 26938800 |
| 11 | 355509000 |
| 12 | 4920379200 |
| 13 | 71753338800 |
| 14 | 1104107484480 |
| 15 | 17923866760800 |
| 16 | 306665482905600 |
| 17 | 5521899225024000 |
| 18 | 104470579944195840 |
| 19 | 2073203785324575360 |