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 | 1 |
| 2 | 12 |
| 3 | 252 |
| 4 | 7560 |
| 5 | 294840 |
| 6 | 14152320 |
| 7 | 806682240 |
| 8 | 53241027840 |
| 9 | 3993077088000 |
| 10 | 335418475392000 |
| 11 | 31193918211456000 |
| 12 | 3181779657568512000 |
| 13 | 353177541990104832000 |
| 14 | 42381305038812579840000 |
| 15 | 5467188350006822799360000 |
| 16 | 754471992300941546311680000 |
| 17 | 110907382868238407307816960000 |
| 18 | 17301551727445191540019445760000 |