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 | -17 |
| 4 | -143 |
| 5 | -1601 |
| 6 | -22419 |
| 7 | -377217 |
| 8 | -7415743 |
| 9 | -166854657 |
| 10 | -4229195779 |
| 11 | -119251176881 |
| 12 | -3702809175823 |
| 13 | -125546570425537 |
| 14 | -4615357640315603 |
| 15 | -182855338776726561 |
| 16 | -7766868454872857599 |
| 17 | -352082642456714366977 |
| 18 | -16965451818345573907843 |