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 | 240 |
| 5 | 332400 |
| 6 | 105480720 |
| 7 | 7787433360 |
| 8 | 233556076320 |
| 9 | 3881511113760 |
| 10 | 42569914312800 |
| 11 | 342908176422240 |
| 12 | 2176503575487120 |
| 13 | 11428762115181840 |
| 14 | 51423745096804080 |
| 15 | 203533610650297200 |
| 16 | 722989464927562560 |
| 17 | 2341382980699049280 |
| 18 | 6999973732130650560 |