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 | -1 |
| 3 | -1 |
| 4 | 8 |
| 5 | -14 |
| 6 | -46 |
| 7 | 314 |
| 8 | 48 |
| 9 | -7244 |
| 10 | 13484 |
| 11 | 233804 |
| 12 | -1002112 |
| 13 | -10692824 |
| 14 | 79853864 |
| 15 | 661278344 |
| 16 | -7758425472 |
| 17 | -52788251504 |
| 18 | 928828095344 |
| 19 | 5226295555184 |
| 20 | -135732896444032 |
| 21 | -617858881186784 |
| 22 | 23892314499643424 |
| 23 | 83518025870961824 |