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 | -1 |
| 4 | -1 |
| 5 | -810129131 |
| 6 | -1220845804166146754 |
| 7 | 6964187975677595099156927503004398881 |
| 8 | 14553806122642016769237504145596730952769427034161327480375008633175279343120 |