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 | 0 |
| 3 | -1 |
| 4 | -6 |
| 5 | -78 |
| 6 | -1544 |
| 7 | -40605 |
| 8 | -1328178 |
| 9 | -51857806 |
| 10 | -2350025232 |
| 11 | -121120896906 |
| 12 | -6991877399100 |
| 13 | -446673990116508 |
| 14 | -31277285155060464 |
| 15 | -2381645560450404989 |
| 16 | -195914136385421694954 |
| 17 | -17312472044077536945630 |
| 18 | -1635541992950202705979424 |
| 19 | -164494265246550280147797438 |