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 | 1 |
| 2 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | -17 |
| 6 | 406 |
| 7 | -1437 |
| 8 | 20476 |
| 9 | -44907 |
| 10 | 1068404 |
| 11 | -5112483 |
| 12 | 230851094 |
| 13 | -1942311373 |
| 14 | 31916614874 |
| 15 | -27260241361 |
| 16 | 3826126294680 |
| 17 | -37957167335671 |
| 18 | 2169009251237640 |
| 19 | -25847377785179111 |
| 20 | 858747698098918338 |
| 21 | -5611513985867158697 |
| 22 | 154094365406716365118 |