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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | -3 |
| 5 | -5 |
| 6 | -14 |
| 7 | -8 |
| 8 | 69 |
| 9 | -435 |
| 10 | 2065 |
| 11 | 3612 |
| 12 | 28888 |
| 13 | -43355 |
| 14 | -2616119 |
| 15 | 28076979 |
| 16 | -332513754 |
| 17 | 331948240 |
| 18 | 8280062505 |
| 19 | 641260644409 |
| 20 | 18784454671297 |
| 21 | -318128427505160 |
| 22 | 10663732503571536 |
| 23 | -66316334575107447 |
| 24 | -8938035295591025771 |
| 25 | -588310630753491921045 |