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 | 2 |
| 2 | 4 |
| 3 | -16 |
| 4 | -256 |
| 5 | -3072 |
| 6 | -81920 |
| 7 | -524288 |
| 8 | 184549376 |
| 9 | 20401094656 |
| 10 | 3848290697216 |
| 11 | 932385860354048 |
| 12 | -229683580995895296 |
| 13 | -514202991054653751296 |
| 14 | -608004684669466821263360 |
| 15 | -1669526556887802890269229056 |
| 16 | -2074787505842297340730932199424 |
| 17 | 33552176086840775798814740439891968 |