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 | 0 |
| 3 | 1 |
| 4 | 10 |
| 5 | 218 |
| 6 | 10078 |
| 7 | 896756 |
| 8 | 151676112 |
| 9 | 47754337568 |
| 10 | 28229412456056 |
| 11 | 31665593711174080 |