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 | -7 |
| 3 | 73 |
| 4 | -1135 |
| 5 | 24241 |
| 6 | -659767 |
| 7 | 21796153 |
| 8 | -846456415 |
| 9 | 37772943841 |
| 10 | -1904103268327 |
| 11 | 106992035096233 |
| 12 | -6630198107231695 |
| 13 | 449171668238551441 |
| 14 | -33024202381308836887 |
| 15 | 2618743082761141212313 |
| 16 | -222782402553043700662975 |
| 17 | 20238957866498067052271041 |