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 | 1 |
| 3 | 3 |
| 4 | 12 |
| 5 | 120 |
| 6 | 2160 |
| 7 | 45360 |
| 8 | 2903040 |
| 9 | 235146240 |
| 10 | 47029248000 |
| 11 | 2586608640000 |
| 12 | 4469659729920000 |
| 13 | 348633458933760000 |
| 14 | 307494710779576320000 |
| 15 | 553490479403237376000000 |
| 16 | 2267097003635660292096000000 |
| 17 | 308325192494449799725056000000 |