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 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | 0 |
| 4 | -1 |
| 5 | 1 |
| 6 | -2 |
| 7 | 7 |
| 8 | -347 |
| 9 | 41781874 |
| 10 | -72939661777729919216033 |
| 11 | 388053169934428398618745564559557538054223536478283729487028027756061 |