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 | 0 |
| 2 | -1 |
| 3 | -3 |
| 4 | -5 |
| 5 | 10 |
| 6 | 134 |
| 7 | 742 |
| 8 | 2325 |
| 9 | -2820 |
| 10 | -118756 |
| 11 | -1138368 |
| 12 | -7132025 |
| 13 | -20945990 |
| 14 | 196411214 |
| 15 | 4438271692 |
| 16 | 50498101545 |
| 17 | 400644382200 |
| 18 | 1571151012344 |
| 19 | -16415635331328 |
| 20 | -500300343321365 |
| 21 | -7486919544207050 |
| 22 | -81415563206142166 |
| 23 | -563533196469890228 |