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 | 0 |
| 3 | -1 |
| 4 | 4 |
| 5 | 7 |
| 6 | -74 |
| 7 | 23 |
| 8 | 2136 |
| 9 | -7345 |
| 10 | -77006 |
| 11 | 712879 |
| 12 | 2499124 |
| 13 | -69799897 |
| 14 | 88342398 |
| 15 | 7311735143 |
| 16 | -50617554896 |
| 17 | -762825930977 |
| 18 | 12821702643946 |
| 19 | 56041362405119 |
| 20 | -2956159258069044 |
| 21 | 8447845572175031 |
| 22 | 660257137187089270 |
| 23 | -7376306690095890185 |