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 | 120 |
| 2 | 210 |
| 3 | 720 |
| 4 | 5040 |
| 5 | 175560 |
| 6 | 17297280 |
| 7 | 19958400 |
| 8 | 259459200 |
| 9 | 20274183401472000 |
| 10 | 25852016738884976640000 |
| 11 | 368406749739154248105984000000 |