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 | 0 |
| 1 | 1 |
| 2 | 2 |
| 3 | 5 |
| 4 | 12 |
| 5 | 1 |
| 6 | -450 |
| 7 | -6931 |
| 8 | -89096 |
| 9 | -1120895 |
| 10 | -14394150 |
| 11 | -191263051 |
| 12 | -2638282812 |
| 13 | -37716883775 |
| 14 | -556075744042 |
| 15 | -8385570334051 |
| 16 | -127637336779920 |
| 17 | -1916072623603199 |
| 18 | -27033275598036174 |
| 19 | -311878728377256475 |
| 20 | -918069644450841860 |
| 21 | 120594465496571606401 |
| 22 | 6362190374664242284782 |