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 | 0 |
| 4 | -3 |
| 5 | 9 |
| 6 | -16 |
| 7 | 13 |
| 8 | 29 |
| 9 | -157 |
| 10 | 391 |
| 11 | -562 |
| 12 | -32 |
| 13 | 3002 |
| 14 | -10373 |
| 15 | 20747 |
| 16 | -18083 |
| 17 | -47941 |
| 18 | 271117 |
| 19 | -712216 |
| 20 | 1066699 |
| 21 | 122131 |
| 22 | -6464446 |
| 23 | 22907125 |
| 24 | -46951992 |
| 25 | 40883304 |
| 26 | 120187926 |
| 27 | -679375906 |
| 28 | 1809757015 |
| 29 | -2731745887 |
| 30 | -468147579 |
| 31 | 17768126376 |
| 32 | -63256877763 |