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 | -20 |
| 4 | -197 |
| 5 | -2511 |
| 6 | -38924 |
| 7 | -708105 |
| 8 | -14769175 |
| 9 | -347328540 |
| 10 | -9093250277 |
| 11 | -262350229095 |
| 12 | -8271756463988 |
| 13 | -283017783855881 |
| 14 | -10445207569804687 |
| 15 | -413662097635230500 |
| 16 | -17499340294430480565 |
| 17 | -787591765696468470799 |
| 18 | -37578217833375886576604 |