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 | 1 |
| 1 | 11 |
| 2 | 105 |
| 3 | 1020 |
| 4 | 10500 |
| 5 | 115920 |
| 6 | 1375920 |
| 7 | 17539200 |
| 8 | 239500800 |
| 9 | 3492720000 |
| 10 | 54226972800 |
| 11 | 893577484800 |
| 12 | 15583119552000 |
| 13 | 286816578048000 |
| 14 | 5557616064000000 |
| 15 | 113108602134528000 |
| 16 | 2412627824775168000 |