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 | 1 |
| 2 | 6 |
| 3 | 54 |
| 4 | 792 |
| 5 | 18360 |
| 6 | 628560 |
| 7 | 29801520 |
| 8 | 1864114560 |
| 9 | 148458925440 |
| 10 | 14652778694400 |
| 11 | 1754531487878400 |
| 12 | 250496910657100800 |
| 13 | 42032247882174950400 |
| 14 | 8188505926902446745600 |
| 15 | 1832839841627736125184000 |
| 16 | 467088574163438830546944000 |