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 | -1 |
| 3 | -2 |
| 4 | 9 |
| 5 | -4 |
| 6 | -95 |
| 7 | 414 |
| 8 | 49 |
| 9 | -10088 |
| 10 | 55521 |
| 11 | -13870 |
| 12 | -2024759 |
| 13 | 15787188 |
| 14 | -28612415 |
| 15 | -616876274 |
| 16 | 7476967905 |
| 17 | -32522642896 |
| 18 | -209513308607 |
| 19 | 4924388011050 |
| 20 | -38993940088199 |
| 21 | 11731860520780 |
| 22 | 3807154270837281 |