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 | 3 |
| 3 | -5 |
| 4 | -107 |
| 5 | 1041 |
| 6 | 20701 |
| 7 | -440033 |
| 8 | -8464455 |
| 9 | 343190593 |
| 10 | 5639857561 |
| 11 | -423764450889 |
| 12 | -4968055259771 |
| 13 | 754544622295153 |
| 14 | 3846355902999429 |
| 15 | -1818148417882379729 |
| 16 | 6637679490204153841 |
| 17 | 5658469355898945338625 |
| 18 | -84578525845602646639823 |