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 | -6 |
| 3 | 81 |
| 4 | -1776 |
| 5 | 54240 |
| 6 | -2125122 |
| 7 | 101631558 |
| 8 | -5739235128 |
| 9 | 373745355984 |
| 10 | -27572590788480 |
| 11 | 2272763834553168 |
| 12 | -207013811669644680 |
| 13 | 20647997125333476912 |
| 14 | -2238256520486195804280 |
| 15 | 262010379635788799196360 |
| 16 | -32939968662220720559744448 |