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 | 13 |
| 3 | -181 |
| 4 | 3865 |
| 5 | -140521 |
| 6 | 6324517 |
| 7 | -344747677 |
| 8 | 23853473329 |
| 9 | -1996865965009 |
| 10 | 193406280000061 |
| 11 | -21615227339380357 |
| 12 | 2778071540350106953 |
| 13 | -403985610499148666041 |
| 14 | 65635628800688339178325 |
| 15 | -11851572489741709802698861 |
| 16 | 2366329597668159364674862177 |