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 | -19 |
| 2 | 517 |
| 3 | -741 |
| 4 | 180119 |
| 5 | -45695 |
| 6 | 1969771 |
| 7 | -2269189 |
| 8 | 466718639 |
| 9 | -107319771 |
| 10 | 47438353385 |
| 11 | -4450937777 |
| 12 | 11033623188467 |
| 13 | -237753881287 |
| 14 | 10639497593899 |
| 15 | 2109652116195 |
| 16 | -48087140237246657 |
| 17 | -3825706373701043 |
| 18 | 6605692011320683297 |
| 19 | 1467932522941406327 |