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 | -4 |
| 3 | 48 |
| 4 | -896 |
| 5 | 22880 |
| 6 | -743232 |
| 7 | 29337280 |
| 8 | -1363752448 |
| 9 | 72979407360 |
| 10 | -4419108684800 |
| 11 | 298730433250304 |
| 12 | -22300928914403328 |
| 13 | 1822195561572585472 |
| 14 | -161756111552270491648 |
| 15 | 15501595224386724126720 |
| 16 | -1595092357302221461127168 |
| 17 | 175405731698165304882495488 |