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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 139 |
| 5 | 16683 |
| 6 | 2876300 |
| 7 | 703845255 |
| 8 | 235994839738 |
| 9 | 105035943170557 |