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 | 5040 |
| 8 | 35280 |
| 9 | 287280 |
| 10 | 2656080 |
| 11 | 27422640 |
| 12 | 312273360 |
| 13 | 3884393520 |
| 14 | 52370755920 |
| 15 | 760381337520 |
| 16 | 11824686110160 |
| 17 | 196038409800240 |
| 18 | 3450899827705680 |
| 19 | 64272619406504880 |
| 20 | 1262590566656060880 |
| 21 | 26087355385405781040 |
| 22 | 565510731026706254160 |