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 | 1 |
| 2 | 4 |
| 3 | 96 |
| 4 | 18432 |
| 5 | 35389440 |
| 6 | 815372697600 |
| 7 | 263006617337856000 |
| 8 | 1357366631815981301760000 |
| 9 | 126095668058466123464363212800000 |
| 10 | 234278891648287676839670388023623680000000 |