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 | -3 |
| 2 | -7 |
| 3 | 117 |
| 4 | 497 |
| 5 | -15123 |
| 6 | -95767 |
| 7 | 4116837 |
| 8 | 34741217 |
| 9 | -1921996323 |
| 10 | -20273087527 |
| 11 | 1370953667157 |
| 12 | 17352768515537 |
| 13 | -1386843017916723 |
| 14 | -20479521468959287 |
| 15 | 1888542637550347077 |
| 16 | 31872138933891307457 |
| 17 | -3331009898404800736323 |
| 18 | -63243057486503656319047 |