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 | -5 |
| 4 | 5 |
| 5 | 56 |
| 6 | -29 |
| 7 | -923 |
| 8 | -119 |
| 9 | 19855 |
| 10 | 17711 |
| 11 | -524160 |
| 12 | -926771 |
| 13 | 16339441 |
| 14 | 45275035 |
| 15 | -585443909 |
| 16 | -2298643951 |
| 17 | 23626165600 |
| 18 | 124604211943 |
| 19 | -1056587815835 |
| 20 | -7261611779179 |
| 21 | 51645640102519 |
| 22 | 455056929514067 |
| 23 | -2724884512463520 |
| 24 | -30595315890959975 |